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Dr. David O'Regan
Associate Professor, Physics

Biography

David completed his PhD at the Cavendish Laboratory, University of Cambridge, in 2011, after which he carried out post-doctoral research first there, and then at the École Polytechnique Fédérale de Lausanne (EPFL). In 2014, he came to Trinity College Dublin and founded what is now the Quantum Theory of Materials Group. David is an Associate Professor in the School of Physics, a CRANN Institute Principal Investigator with an affiliation to the SFI AMBER Research Centre, and a Fellow of Trinity College Dublin since 2022.

David's research is dedicated to finding unexpected, innovative ways to transform the accuracy, efficiency, and applicability of theory and simulation software for understanding the material world using quantum mechanics. He is known for his work on simulating, from the electrons up, systems that are both spatially complex (e.g., disordered crystals or molecules) and harbour strong interactions that are beyond the predictive capacity of standard techniques.

David is particularly known for his work on extending and refining the class of methods known as constrained DFT and DFT+U. David is actively involved in the development of linear-scaling density functional theory. Here, he implements and improve corrective approaches such as DFT+U, constrained DFT and DFT+DMFT in addition to researching new Wannierisation and time-propagation (TDDFT) algorithms. David maintains a long-term programme in the development of tractable and user-friendly methods moving beyond Kohn-Sham DFT, via the density-matrix and Green's function, not only for spectra but for energies and their derivatives. He's interested in magnetic and multiple-valence properties, generally, and optical, magneto-optical, and photoemission spectroscopies. A particular focus is placed on these properties as exhibited by transition-metal comprising materials, complexes, and nanostructures.

David's recent grants and awards include the EPSRC-SFI Joint Funding of Research award, SFI AMBER II Funded Investigator status, an AMBER Director's Fund award, a Trinity Provost's PhD Project award, Irish Research Council postgraduate award mentorship, leadership of a competitively-awarded College infrastructure project, as well as research partnership with industry and sponsorship from Enterprise Ireland and the Royal Irish Academy.

At Trinity, David has recently served as Director of Teaching & Learning (Undergraduate), Physics (3 years); Chair, School of Physics Teaching & Learning Committee; Member, Central Scholarship Committee (current); College Tutor (6 years); Member, School Executive Committee; Member, Trinity Undergraduate Studies Committee; Member, Institutional Academic Integrity Working Group; Member (current), School Athena SWAN Committee, Member (current), Theoretical Physics Degree Course Committee. In previous years he has served as School of Physics Examinations Coordinator; Chair, School of Physics Resumption of Teaching Steering Committee; CRANN seminar series Convenor; Coordinator of the School of Physics Summer Undergraduate Research Experience (SURE) programme, and as the Theoretical Physics Degree Coordinator in Physics.

Publications and Further Research Outputs

Peer-Reviewed Publications

Burgess A.C., Linscott E., O'Regan D.D., Tilted-Plane Structure of the Energy of Finite Quantum Systems, Physical Review Letters, 133, (2), 2024 Journal Article, 2024 DOI

MacEnulty L., Giantomassi M., Amadon B., Rignanese G.-M., O'Regan D.D., Facilities and practices for linear response Hubbard parameters U and J in Abinit, Electronic Structure, 6, (3), 2024 Journal Article, 2024 DOI

Chai, Ziwei, Si, Rutong, Chen, Mingyang, Teobaldi, Gilberto, O;Regan, David D., Liu, Li-Min, Minimum Tracking Linear Response Hubbard and Hund Corrected Density Functional Theory in CP2K, Journal of Chemical Theory and Computation, 20, (20), 2024, p8984-9002 Journal Article, 2024 DOI

Burgess, Andrew C., O'Regan, David D., Flat plane based double-counting free and parameter free many-body DFT+U, Physical Review B, 110, (20), 2024 Journal Article, 2024 DOI

Moore G.C., Horton M.K., Linscott E., Ganose A.M., Siron M., O'Regan D.D., Persson K.A., High-throughput determination of Hubbard U and Hund J values for transition metal oxides via the linear response formalism, Physical Review Materials, 8, (1), 2024 Journal Article, 2024 DOI

Bhandary S., Poli E., Teobaldi G., O'Regan D.D., Dynamical Screening of Local Spin Moments at Metal-Molecule Interfaces, ACS Nano, 17, (6), 2023, p5974 - 5983 Journal Article, 2023 DOI

Burgess A.C., Linscott E., O'Regan D.D., DFT+U-type functional derived to explicitly address the flat plane condition, Physical Review B, 107, (12), 2023 Journal Article, 2023 DOI

Murray, Christopher P., Mamyraimov, Daniyar, Ali, Mugahid, Downing, Clive, Povey, Ian M., McCloskey, David, O'Regan, David D., Donegan, John F., Monolayer Capping Provides Close to Optimal Resistance to Laser Dewetting of Au Films, ACS Applied Electronic Materials, 5, (8), 2023, p4080-4093 Journal Article, 2023 DOI

Berman S., Zhussupbekova A., Boschker J.E., Schwarzkopf J., O'Regan D.D., Shvets I.V., Zhussupbekov K., Reconciling the theoretical and experimental electronic structure of NbO2, Physical Review B, 108, (15), 2023, p155141- Journal Article, 2023 DOI

MacEnulty L., O'Regan D.D., Optimization strategies developed on NiO for Heisenberg exchange coupling calculations using projector augmented wave based first-principles DFT+U+J, Physical Review B, 108, (24), 2023 Journal Article, 2023 DOI

Halder, Anita, Bhandary, Sumanta, O'Regan, David D., Sanvito, Stefano, Droghetti, Andrea, Theoretical perspective on the modification of the magnetocrystalline anisotropy at molecule-cobalt interfaces, Physical Review Materials, 7, (6), 2023, p064409- Journal Article, 2023 DOI

Lambert, D. S., O'Regan, D. D., Use of DFT+U+J with linear response parameters to predict non-magnetic oxide band gaps with hybrid-functional accuracy, Physical Review Research, 5, (1), 2023 Journal Article, 2023 DOI

Berman S., Zhussupbekova A., Walls B., Walshe K., Bozhko S.I., Ionov A., O'Regan D.D., Shvets I.V., Zhussupbekov K., Unraveling the atomic and electronic structure of nanocrystals on superconducting Nb(110): Impact of the oxygen monolayer, Physical Review B, 107, (16), 2023 Journal Article, 2023 DOI

Burgess A.C., Linscott E., O'Regan D.D., The convexity condition of density-functional theory, Journal of Chemical Physics, 159, (21), 2023 Journal Article, 2023 DOI

Zotti L. A., O'Regan D. D., Adhesion of thin metallic layers on Au surfaces, Journal of Physics Condensed Matter, 34, (27), 2022 Journal Article, 2022 DOI

Alotibi S, Hickey BJ, Teobaldi G, Ali M, Barker J, Poli E, O'Regan DD, Ramasse Q, Burnell G, Patchett J, Ciccarelli C, Alyami M, Moorsom T, Cespedes O., Enhanced Spin-Orbit Coupling in Heavy Metals via Molecular Coupling., ACS Applied Materials & Interfaces, 13, (4), 2021, p5228-5234 Journal Article, 2021 DOI

Almohammed, Sawsan, K. Orhan, Okan, Daly, Sorcha, O'Regan, David D., Rodriguez, Brian J., Casey, Eoin, Rice, James H., Electric Field Tunability of Photoluminescence from a Hybrid Peptide-Plasmonic Metal Microfabricated Chip, JACS Au, 1, (11), 2021, p1987-1995 Journal Article, 2021 DOI

Kenan Elibol, Clemens Mangler, David D. O'Regan, Kimmo Mustonen, Dominik Eder, Jannik C. Meyer, Jani Kotakoski, Richard G. Hobbs, Toma Susi, and Bernhard C. Bayer, Single Indium Atoms and Few-Atom Indium Clusters Anchored onto Graphene via Silicon Heteroatoms, ACS Nano, 15, (9), 2021, p14373-14383 Journal Article, 2021 URL

Zhussupbekov, Kuanysh, Walshe, Killian, Walls, Brian, Ionov, Andrei, Bozhko, Sergei I., Ksenz, Andrei, Mozhchil, Rais N., Zhussupbekova, Ainur, Fleischer, Karsten, Berman, Samuel, Zhilyaev, Ivan, O'Regan, David D., Shvets, Igor V., Surface Modification and Subsequent Fermi Density Enhancement of Bi(111), The Journal of Physical Chemistry C, 125, (10), 2021, p5549-5558 Journal Article, 2021 DOI

Almohammed, S., Fularz, A., Zhang, F., Alvarez-Ruiz, D., Bello, F., O'Regan, D.D., Rodriguez, B.J., Rice, J.H., Flexing Piezoelectric Diphenylalanine-Plasmonic Metal Nanocomposites to Increase SERS Signal Strength, ACS Applied Materials and Interfaces, 12, (43), 2020, p48874-48881 Journal Article, 2020 DOI

Orhan, O.K., O'Regan, D.D., First-principles Hubbard U and Hund's J corrected approximate density functional theory predicts an accurate fundamental gap in rutile and anatase TiO2, Physical Review B, 101, (24), 2020, p245137- Journal Article, 2020 DOI

Rangel, T. and Del Ben, M. and Varsano, D. and Antonius, G. and Bruneval, F. and da Jornada, F.H. and van Setten, M.J. and Orhan, O.K. and O'Regan, D.D. and Canning, A. and Ferretti, A. and Marini, A. and Rignanese, G.-M. and Deslippe, J. and Louie, S.G. and Neaton, J.B., Reproducibility in G0W0 calculations for solids, Computer Physics Communications, 255, (107242), 2020 Journal Article, 2020 DOI

Rangel, T., Del Ben, M., Varsano, D., Antonius, G., Bruneval, F., da Jornada, F.H., van Setten, M.J., Orhan, O.K., O'Regan, D.D., Canning, A., Ferretti, A., Marini, A., Rignanese, G.-M., Deslippe, J., Louie, S.G., Neaton, J.B., Reproducibility in G0W0 calculations for solids, Computer Physics Communications, 255, 2020, p107242- Journal Article, 2020 DOI

MacEnulty, Lórien, O'Regan, David D., Calculation of the Magnetostatic Energy in Spin Density Functional Theory, Journal of Undergraduate Reports in Physics, 30, (1), 2020, p100005 Journal Article, 2020 DOI

Roychoudhury S, Sanvito S, O'Regan DD., Neutral excitation density-functional theory: an efficient and variational first-principles method for simulating neutral excitations in molecules., Scientific reports, 10, (1), 2020, p8947 Journal Article, 2020 TARA - Full Text DOI

Prentice J.C.A., Aarons J., Womack J.C., Allen A.E.A., Andrinopoulos L., Anton L., Bell R.A., Bhandari A., Bramley G.A., Charlton R.J., Clements R.J., Cole D.J., Constantinescu G., Corsetti F., Dubois S.M.-M., Duff K.K.B., Escartin J.M., Greco A., Hill Q., Lee L.P., Linscott E., O'Regan D.D., Phipps M.J.S., Ratcliff L.E., Serrano A.R., Tait E.W., Teobaldi G., Vitale V., Yeung N., Zuehlsdorff T.J., Dziedzic J., Haynes P.D., Hine N.D.M., Mostofi A.A., Payne M.C., Skylaris C.-K., The ONETEP linear-scaling density functional theory program, Journal of Chemical Physics, 152, (17), 2020 Journal Article, 2020 DOI

Bello, F. and Orhan, O.K. and Abadia, N. and O'Regan, D.D. and Donegan, J.F., Material Characterization and Thermal Performance of Au Alloys in a Thin-Film Plasmonic Waveguide, OSA Technical Digest, CLEO: Applications and Technology 2019,, San Jose, California United States, , 5-10 May, (8749235), 2019, JTu2A.110- Conference Paper, 2019 DOI URL

Orhan, O.K., O'Regan, D.D., TDDFT+U: A critical assessment of the Hubbard U correction to exchange-correlation kernels and potentials, Physical Review B, 99, (16), 2019 Journal Article, 2019 DOI

Orhan, O.K., O'Regan, D.D., Plasmonic performance of AuxAgyCu1-x-y alloys from many-body perturbation theory, Journal of Physics Condensed Matter, 31, (31), 2019 Journal Article, 2019 DOI

Orhan, O.K. and O'Regan, D.D., Plasmonic performance of AuxAgyCu1-x-y alloys from many-body perturbation theory, Journal of Physics Condensed Matter, 31, (31), 2019 Journal Article, 2019 DOI

Backes C, Campi D, Szydlowska BM, Synnatschke K, Ojala E, Rashvand F, Harvey A, Griffin A, Sofer Z, Marzari N, Coleman JN, O'Regan DD., Equipartition of Energy Defines the Size-Thickness Relationship in Liquid-Exfoliated Nanosheets., ACS Nano, 13, (6), 2019, p7050-7061 Journal Article, 2019 DOI TARA - Full Text

Roychoudhury, S. and O'Regan, D.D. and Sanvito, S., Wannier-function-based constrained DFT with nonorthogonality-correcting Pulay forces in application to the reorganization effects in graphene-adsorbed pentacene, Physical Review B, 97, (20), 2018, p085303- Journal Article, 2018 DOI TARA - Full Text

Linscott, E.B., Cole, D.J., Payne, M.C., O'Regan, D.D., Role of spin in the calculation of Hubbard U and Hund's J parameters from first principles, Physical Review B, 98, (23), 2018 Journal Article, 2018 DOI

Linda A. Zotti, S. Sanvito, and David D. O'Regan, A simple descriptor for energetics at fcc-bcc metal interfaces, Materials & Design, 142, 2018, p158 - 165 Journal Article, 2018 DOI

Glenn Moynihan, Stefano Sanvito, and David D. O'Regan, Strain-induced Weyl and Dirac states and direct-indirect gap transitions in group-V materials, 2D Materials, 4, (4), 2017, p045018 Journal Article, 2017 DOI TARA - Full Text

Emilio Artacho and David D. O'Regan, Quantum mechanics in an evolving Hilbert space, Physical Review B, 95, (11), 2017, p5155 Journal Article, 2017 DOI

D. D. O'Regan and G. Teobaldi, Optimization of constrained density functional theory, Physical Review B, 94, (3), 2016 Journal Article, 2016 DOI

David H. P. Turban, Gilberto Teobaldi, David D. O'Regan, and Nicholas D. M. Hine, Supercell convergence of charge-transfer energies in pentacene molecular crystals from constrained DFT, Physical Review B, 93, (16), 2016 Journal Article, 2016 DOI

Glenn Moynihan, Gilberto Teobaldi, and David D. O'Regan, Inapplicability of exact constraints and a minimal two-parameter generalization to the DFT+$U$ based correction of self-interaction error, Physical Review B, 94, (22), 2016, p220104(R) Journal Article, 2016 DOI

Hanlon D, Backes C, Doherty E, Cucinotta CS, Berner NC, Boland C, Lee K, Harvey A, Lynch P, Gholamvand Z, Zhang S, Wang K, Moynihan G, Pokle A, Ramasse QM, McEvoy N, Blau WJ, Wang J, Abellan G, Hauke F, Hirsch A, Sanvito S, O'Regan DD, Duesberg GS, Nicolosi V, Coleman JN, Liquid exfoliation of solvent-stabilized few-layer black phosphorus for applications beyond electronics., Nature communications, 6, 2015, p8563 Journal Article, 2015 TARA - Full Text DOI

Weber C., Cole D.J., O'Regan D.D., Payne M.C., Renormalization of myoglobin-ligand binding energetics by quantum many-body effects, Proceedings of the National Academy of Sciences of the United States of America, 111, (16), 2014, p5790 - 5795, p5790-5795 Journal Article, 2014 DOI

Weber, C., O'Regan, D.D., Hine, N.D.M., Littlewood, P.B., Kotliar, G., Payne, M.C., Importance of many-body effects in the kernel of hemoglobin for ligand binding, Physical Review Letters, 110, (10), 2013 Journal Article, 2013 DOI URL

Heiss, M., Fontana, Y., Gustafsson, A., Wüst, G., Magen, C., O'Regan, D.D., Luo, J.W., Ketterer, B., Conesa-Boj, S., Kuhlmann, A.V., Houel, J., Russo-Averchi, E., Morante, J.R., Cantoni, M., Marzari, N., Arbiol, J., Zunger, A., Warburton, R.J., Fontcuberta I Morral, A., Self-assembled quantum dots in a nanowire system for quantum photonics, Nature Materials, 12, (5), 2013, p439-444 Journal Article, 2013 URL DOI

O'Regan, D.D., Hine, N.D.M., Payne, M.C., Mostofi, A.A., Linear-scaling DFT+U with full local orbital optimization, Physical Review B - Condensed Matter and Materials Physics, 85, (8), 2012 Journal Article, 2012 URL DOI

O'Regan, David D., Optimised Projections for the Ab Initio Simulation of Large and Strongly Correlated Systems, Springer Berlin Heidelberg, 2012 Book, 2012 DOI

Weber, C., O'Regan, D.D., Hine, N.D.M., Payne, M.C., Kotliar, G., Littlewood, P.B., Vanadium dioxide: A Peierls-Mott insulator stable against disorder, Physical Review Letters, 108, (25), 2012 Journal Article, 2012 DOI URL

Cole, D.J., O'Regan, D.D., Payne, M.C., Ligand discrimination in myoglobin from linear-scaling DFT+ U, Journal of Physical Chemistry Letters, 3, (11), 2012, p1448-1452 Journal Article, 2012 URL DOI

O'Regan, D.D., Payne, M.C., Mostofi, A.A., Generalized Wannier functions: A comparison of molecular electric dipole polarizabilities, Physical Review B - Condensed Matter and Materials Physics, 85, (19), 2012 Journal Article, 2012 DOI URL

O'Regan, D.D., Payne, M.C., Mostofi, A.A., Subspace representations in ab initio methods for strongly correlated systems, Physical Review B - Condensed Matter and Materials Physics, 83, (24), 2011 Journal Article, 2011 DOI URL

O'Regan, D.D., Hine, N.D.M., Payne, M.C., Mostofi, A.A., Projector self-consistent DFT+U using nonorthogonal generalized Wannier functions, Physical Review B - Condensed Matter and Materials Physics, 82, (8), 2010 Journal Article, 2010 URL DOI

Non-Peer-Reviewed Publications

A. Cabero del Hierro, K. Zhussupbekov, S. Berman, D. Spurling, A. Zhussupbekova, D. D. O'Regan, I. V. Shvets, and V. Nicolosi, Self-assembled Moiré superstructure of MXene", DPG Spring Meeting of the Condensed Matter Section 2024, Berlin, Germany, 2024 Poster, 2024

A. C. Burgess, E. Linscott, and D. D. O'Regan, Error Correction Methods for Local & Semi-Local DFT, International HPC Summer SchooL 2024, Kobe, Japan, 2024 Poster, 2024

S. Bhandary, E. Poli, G. Teobaldi, and D. D. O'Regan, Dynamical screening of the local spin moments at metal-molecule spintronic interfaces, ACS Spring 2024 National Meeting and Exposition, New Orleans, USA, 2024 Oral Presentation, 2024

D. D. O'Regan, The DFT+U method for strongly-correlated and mixed-valence systems, ONETEP Masterclass 2024, Rutherford Appleton Laboratory, UK, 2024 Invited Talk, 2024

A. C. Burgess, E. Linscott, and D. D. O'Regan, Towards exactified DFT+U total energies via the flat plane condition: the BLOR functional, ACS Spring 2024 National Meeting and Exposition, New Orleans, USA, 2024 Oral Presentation, 2024

D. S. Lambert and D. D. O'Regan, First-principles DFT+U+J approach to metal oxide simulation: TiO2, ZrO2, HfO2, Cu2O and ZnO, ACS Spring 2024 National Meeting and Exposition, New Orleans, USA, 2024 Oral Presentation, 2024

L. MacEnulty and D. D. O'Regan, Assessing total energy differences from first-principles DFT+U+J using Heisenberg model mappings of NiO, ACS Fall Meeting 2024, Denver, USA, 2024 Poster, 2024

L. MacEnulty, J.P.A. de Mendonça, R. Poloni, and D. D. O'Regan, Breakdown and potential remedies for DFT+U total energy differences and linear-response parameter calculations in spin-crossover complexes, ACS Fall Meeting 2024, Denver, USA, 2024 Poster, 2024

D. S. Lambert and D. D. O'Regan, Accurate modelling of oxide bandgaps and defect levels using first principles DFT+U+J, AMBER Conference 2024, Dublin, 2024 Poster, 2024

K. Zhussupbekov, A. Cabero del Hierro, S. Berman, D. Spurling, A. Zhussupbekova, D. O'Regan, I. Shvets, and V. Nicolosi, Self-assembled Moiré superstructure of MXene, MRS Spring Meeting and Exhibit, Seattle, USA, 2024 Oral Presentation, 2024

L. MacEnulty and D. D. O'Regan, Assessing the reliability and comparability of first-principles DFT+U total-energies via Heisenberg parameters for NiO, ACS Spring 2024 National Meeting and Exposition, New Orleans, USA, 2024 Oral Presentation, 2024

A. C. Burgess, E. Linscott, and D. D. O'Regan, A first-principles DFT+U functional for the flat-plane condition robust against stringent test cases, American Physical Society March Meeting, Minneapolis, USA, 2024 Oral Presentation, 2024

D. D. O'Regan, Towards cost-effective correction of self-interaction and static correlation error on subspaces, Burke Theory Group meeting talk, Online, hosted by UC Irvine, 2024 Invited Talk, 2024

A. C. Burgess, E. Linscott, and D. D. O'Regan, Tilted Plane Condition on the Energy of Finite Fermionic Systems, Progress in Ensemble Density Functional Theory: Opportunities and Challenges, Durham, UK, 2024 Oral Presentation, 2024

A. C. Burgess, E. Linscott, and D. D. O'Regan, Exact double counting correction schemes from the flat plane condition, American Physical Society March Meeting, Minneapolis, USA, 2024 Poster, 2024

A. C. Burgess, E. Linscott, and D. D. O'Regan, In situ correction of self-interaction & static correlation errors, 20th International Conference on Density Functional Theory and its Applications (DFT 2024), Paris, France, 2024 Poster, 2024

A. C. Burgess, E. Linscott, and D. D. O'Regan, The Tilted Plane Condition, 20th International Conference on Density Functional Theory and its Applications (DFT 2024), Paris, France, 2024 Poster, 2024

L. MacEnulty, J.P.A. de Mendonça, R. Poloni, and D. D. O'Regan, Breakdown and potential remedies for DFT+U total energy differences and linear-response parameter calculations in spin-crossover complexes, ACS Fall Meeting 2024, Denver, USA, 2024 Oral Presentation, 2024

A. C. Burgess, E. Linscott, and D. D. O'Regan, A DFT+U-type functional to correct both self interaction error and static correlation error, 17th International Congress of Quantum Chemistry, Bratislava, Slovakia, 2023 Poster, 2023

L. MacEnulty (Speaker) and D. D. O'Regan, Navigating the interference of Hubbard Corrections and magnetic model mappings in Approximate DFT, Seminar, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK, 2023 Invited Talk, 2023

A. Droghetti (Speaker), A. Halder, S. Bhandary, D. D. O'Regan, S. Sanvito, M. M. Radonjic, I. Rungger, L. Chioncel, Exploring magnetic properties and electron correlation effects at hybrid interfaces, CMD30 FisMat 2023, Milan, Italy, 2023 Invited Talk, 2023

A. Halder, S. Bhandary, D. D. O'Regan, S. Sanvito, A. Droghetti, Modification of the magnetocrystalline anisotropy at molecule-cobalt interfaces (Awarded Best Poster), Joint European Magnetic Symposia 2023, Madrid, Spain, 2023 Poster, 2023

A. C. Burgess, E. Linscott, and D. D. O'Regan, Capturing static correlation using a new DFT+U-type functional, 3rd Quantum International Frontiers, Lódz, Poland, 2023 Oral Presentation, 2023

D. D. O'Regan, DFT+U+J and constrained DFT in ONETEP, ONETEP Masterclass 2023, Rutherford Appleton Laboratory, UK, 2023 Invited Talk, 2023

L. MacEnulty (Speaker) and D. D. O'Regan, Assessing total energy differences from first principles DFT+U+J using magnetic orderings in NiO, Seminar, Science et ingénierie des matériaux et des procédés (SimAP), Université Grenoble Alpes, Grenoble, France, 2023 Invited Talk, 2023

K. Elibol (Speaker), C. Mangler, D. D. O'Regan, K. Mustonen, D. Eder, J. C. Meyer, J. Kotakoski, R. G. Hobbs, T. Susi, B. C. Bayer, and P. A. van Aken, Electron beam fabrication of metal clusters on graphene: From Atomic to Nanoscale Integration, 20th International Microscopy Conference, Busan, Korea, 2023 Invited Talk, 2023

L. MacEnulty and D. D. O'Regan, Assessment of first-principles DFT+U+J for NiO: PAW projector dependence and Heisenberg model mappings, Psi-k Conference 2022, Lausanne, Switzerland, 2022 Poster, 2022

S. Berman, K. Zhussupbekov, A. Zhussupbekova, B. Walls, K. Walshe, S. I. Bozhko, A. Ionov, D. D. O'Regan, and I. V. Shvets, Structure of NbO Nanocrystals on the Nb(110) Surface, DPG Meeting of the Condensed Matter Section 2022, Regensburg, Germany, 2022 Oral Presentation, 2022 URL

D. D. O'Regan, First-Principles Hund's J: a Promising yet Intriguing Low-Cost Generalised Kohn-Sham Band-Gap Correction Device, 19th International Conference on Density Functional Theory and its Applications (DFT 2022), Brussels, Belgium, 30th August 2022, 2022 Oral Presentation, 2022 URL

L. MacEnulty and D. D. O'Regan, Projectors and Hubbard Parameters and Abinit: Projectors and Hubbard Parameters and Abinit, Rignanese Research Group Seminar, Institute for Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-La-Neuve, Belgium, 2022 Oral Presentation, 2022 URL

A. Halder, S. Bhandary, D. O'Regan, S. Sanvito, and A. Droghetti, Modification of Magnetic Anisotropy at Organic-Inorganic Interfaces, DPG Spring Meeting of the Condensed Matter Section 2023, Dresden, Germany, 2022 Oral Presentation, 2022

D. Lambert and D. O'Regan, First principles DFT+U+J modelling of bandgaps and defect levels in TiO2, ZrO2 and HfO2, Institute of Physics conference: Dielectrics 2022, London, UK, 2022 Oral Presentation, 2022

S. Bhandary, E. Poli, G. Teobaldi, and D. D. O'Regan, Dynamical screening at the metal-molecule interfaces: a hindrance to molecular spintronic device development?, Psi-k Conference 2022, Lausanne, Switzerland, 2022 Poster, 2022

D. D. O'Regan, First-principles Hund's J correction of approximate DFT, CCP2022: 33rd IUPAP Conference on Computational Physics, Online, hosted by The University of Texas at Austin, 2022 Invited Talk, 2022

A. Burgess, E. Linscott, and D. D. O'Regan, Comparison of Hubbard Functionals for Strongly Correlated Systems, Psi-k Conference 2022, Lausanne, Switzerland, 2022 Poster, 2022

L. MacEnulty and D. D. O'Regan, Linear Response Hubbard U and Hund's J , PAW population analysis, Heisenberg exchange coupling parameters: A three-fold investigation featuring NiO, CCP2022: 33rd IUPAP Conference on Computational Physics, Online, hosted by The University of Texas at Austin, 2022 Oral Presentation, 2022

S. Bhandary, E. Poli, G. Teobaldi and D. D. O'Regan, Dynamical screening at the metal-molecule interface: a hindrance to molecular spintronic device developments?, Joint European Magnetic Symposia 2022, Warsaw, Poland, 2022 Oral Presentation, 2022

L. MacEnulty and D. D. O'Regan, PAW+U+J mapping of NiO onto the magnetic Heisenberg model: best practices, population analysis, and spin-symmetry investigations, ETSF Young Researchers Meeting, Marseille, France, 2022 Oral Presentation, 2022 URL

L. MacEnulty and D. D. O'Regan, First-principles PAW+U (± J) mapping of NiO onto the magnetic Heisenberg model: towards accurate exchange coupling parameters, Paris International School on Advanced Computational Materials Science (PISACMS), Paris, France, 2022 Poster, 2022 URL

D. S. Lambert and D. D. O'Regan, Accurate modelling of oxide bandgaps and defect levels using first principles DFT+U+J, Psi-k Conference 2022, Lausanne, Switzerland, 2022 Poster, 2022

K. Elibol, C. Mangler, D. D. O'Regan, K. Mustonen, D. Eder, J. C. Meyer, J. Kotakoski, R. G. Hobbs, P. A. van Aken, T. Susi, and B. C. Bayer, Self-assembly and heteroatomic anchoring of single indium atoms and few-atom indium clusters on graphene, EUROMAT 2021, Online, 2021 Oral Presentation, 2021 URL

D. D. O'Regan, The partner of the Hubbard U: interpretation of Hund's J in DFT+U methods, linear-response calculations for J, and the results to expect, EPFL THEOS Group & NCCR-MARVEL Seminar, Online and Lausanne, CH, 2021 Invited Talk, 2021 URL

D. D. O'Regan, Force calculations in density-functional theory with extra challenges: Strongly-correlated materials, multi-centre constraints, and time-evolving basis sets, American Chemical Society Fall 2021 National Meeting & Exposition, Online and Atlanta, GA, U.S.A., 2021 Invited Talk, 2021 URL

D. D. O'Regan, O. K. Orhan, G. Moynihan, E. B. Linscott, D. J. Cole, and G. Teobaldi, The partner of the Hubbard U: interpretation of Hund's J in DFT+U methods, Psi-k School "Bridging First-Principles Calculations and Effective Hamiltonians", Online, hosted by IIT Genova, IT, 2021 Oral Presentation, 2021 URL

L. MacEnulty and D. D. O'Regan, Calculation of the Magnetostatic Dipole-Dipole Correction to Periodic Spin-Density Functional Theory Using an Auxiliary Magnetic Charge Density, Materials Research Society (MRS) MRS Spring Meeting and Exhibit, Online, 2021 Poster, 2021 URL

D. D. O'Regan, O. K. Orhan, E. B. Linscott, G. Moynihan, and G. Teobaldi, A linear-response approach for first-principles Hund's J parameters: insights, oxides, and self-consistency, APS March Meeting, Online and Chicago, IL, U.S.A., 2021 Oral Presentation, 2021 URL

Elibol, Kenan, Mangler, Clemens, O'Regan, David D., Mustonen, Kimmo, Eder, Dominik, Meyer, Jannik C., Kotakoski, Jani, Hobbs, Richard G., van Aken, Peter A., Susi, Toma, Bayer, Bernhard C., Single indium atoms and few-atom indium clusters anchored onto graphene via silicon heteroatoms, Microscopy and Microanalysis, 27, (S1), Cambridge University Press , 2021, pp3346-3347 Published Abstract, 2021 DOI

D. P. Gavin and D. D. O'Regan, Quantum-mechanical computational screening and design of resilient plasmonic alloys for ICT and sensing, AMBER ICT Theme Meeting, Trinity College Dublin, IE, 2021 Oral Presentation, 2021

L. MacEnulty and D. D. O'Regan, Hubbard U and Hund's Coupling J Parameters from First Principles: Towards accurate Heisenberg exchange coupling parameters for NiO, QUOROM-V, Online, 2021 Poster, 2021 URL

L. MacEnulty and D. D. O'Regan, On using an auxiliary magnetic charge density to calculate the magnetostatic dipole-dipole correction to spin-density functional theory (DFT), EUROMAT 2021, Online, 2021 Oral Presentation, 2021 URL

D. Lambert and D. D. O'Regan, Systematic Evaluation of First Principles DFT+U+J Algorithms for the Fast and Accurate Modelling of Transition Metal Oxides, MRS Fall Meeting and Exhibit, Online and Boston, MA, U.S.A., 2021 Oral Presentation, 2021 URL

S. Roychoudhury (speaker), S. Sanvito, and D. D. O'Regan, Neutral Excitation Density Functional Theory (won Best Oral Presentation award), Evolution of Electronic Structure Theory and Experimental Realization, Online, organised by SRM IST KTR (India), IIT Madras (India) and Uppsala University (Sweden), 2020 Oral Presentation, 2020 URL

D. P. Gavin, O. K. Orhan, and D. D. O'Regan, Simulation protocols for paramagnetic transition-metal oxides", Total Energy and Force Methods 2020, Donostia-San Sebastián, ES, 2020 Poster, 2020 URL

D. P. Gavin, O. K. Orhan, and D. D. O'Regan, Corrective first-principles approaches for paramagnetic transition-metal oxides, Computational School on Electronic Excitations in Novel Materials Using the Yambo Code, Trieste, IT, 2020 Poster, 2020 URL

K. Elibol, C. Mangler, D. D. O'Regan, K. Mustonen, D. Eder, J. C. Meyer, J. Kotakoski, R. G. Hobbs, T. Susi, and B. C. Bayer, Indium Oligomers anchored via Silicon Heteroatoms onto Graphene, Microscopy Society of Ireland Symposium, Dublin, IE, 2020 Oral Presentation, 2020 URL

D. D. O'Regan, Through thick and thin: A size-thickness power law for liquid-phase exfoliated 2D nanosheets, Materials & Molecular Modelling Hub Conference and User Meeting, University College London, U.K., 2019 Invited Talk, 2019 URL

S. Roychoudhury, D. D. O'Regan, and S. Sanvito, Evaluation of Pulay forces due to change in overlap of subspace-projection orbitals in constrained DFT: Application in calculation of reorganization energy of adsorbed molecule, APS March Meeting, Boston, MA, U.S.A. , 2019 Oral Presentation, 2019 URL

D. D. O'Regan, G. Moynihan, O. K. Orhan, E. B. Linscott, M. C. Payne, G. Teobaldi, and D. J. Cole, Towards automated self-correction of approximate DFT using first-principles Hubbard U and Hund's J parameters, Electronic Structure Discussion Group, University of Cambridge, Cambridge, U.K., 2019 Invited Talk, 2019 URL

S. Roychoudhury, D. D. O'Regan, and S. Sanvito, Pulay Forces with Constrained DFT: Calculation of Reorganization Energy, ONETEP Masterclass 2019: Karl Wilkinson Prize talk, Warwick, UK, 2019 Invited Talk, 2019 URL

D. D. O'Regan, G. Moynihan, E. B. Linscott, O. K. Orhan, G. Teobaldi, D. J. Cole, M. C. Payne, Towards an automated self-correction protocol for approximate DFT: facile first-principles Hubbard U and Hund's J parameters for arbitrary subspaces, Computational Molecular Science Conference, Warwick, U.K., 2019 Invited Talk, 2019 URL

D. D. O'Regan, Challenges in quantum materials simulation meet challenges in green energy, Dublin University Physical Society, Trinity College Dublin, IE, 2019 Invited Talk, 2019

S. Roychoudhury, S. Sanvito, and D. D. O'Regan, Excitonic DFT: An Efficient and Flexible Constrained DFT Approach for Simulating Neutral Excitations in Isolated and Periodic Systems, APS March Meeting, Los Angeles, CA, U.S.A., 2018 Oral Presentation, 2018 URL

D. D. O'Regan, An introduction to modern scholarly publication, Trinity Student Scientific Review IV Launch, Trinity College Dublin, IE, 2018 Invited Talk, 2018

D. D. O'Regan, G. Moynihan, O. K. Orhan, E. B. Linscott, M. C. Payne, G. Teobaldi, and D. J. Cole, Self-consistent Hubbard U and Hund's J parameters for DFT from ground-state tracking linear response, New Generation in Strongly Correlated Electrons Systems, Donostia-San Sebastián, ES, 2018 Invited Talk, 2018 URL

K. Walshe, S. Bozhko, B. Walls, K. Zhussupbekov, D. D. O'Regan, and I.V. Shvets, Surface Defects on Cu (111): A combined STM & DFT study, 34th European Conference on Surface Science, Aarhus, DK, 2018 Oral Presentation, 2018 URL

D. D. O'Regan, G. Moynihan, O. K. Orhan, and G. Teobaldi, A self-contained linear-response approach to constrained DFT, DFT+U, and TDDFT+U, EPFL THEOS Group & NCCR-MARVEL Seminar, Lausanne, CH, 2017 Invited Talk, 2017

O. K. Orhan and D. D. O'Regan, A Hubbard U based correction method for exciton binding in neutral excitations: TDDFT+U, DPG Spring Meeting, Dresden, DE, 2017 Poster, 2017 URL

E. Linscott, D. Cole, D. O'Regan, C. Weber, and M. Payne, Electronic Correlation in Biology: advances and applications of linear-scaling DFT, DFT+U, and DMFT, Autumn School in Correlated Electrons, Forschungszentrum Jülich, Germany, 2017 Poster, 2017 URL

D. D. O'Regan, G. Moynihan, O. K. Orhan, and G. Teobaldi, Linear-Scaling direct-minimization approaches for orbital-based constrained DFT, DFT+U, and beyond, Chair of Theoretical Chemistry Seminar, TU München, Munich, DE, 2017 Invited Talk, 2017 URL

D. D. O'Regan, Hilbert space partitoning and Pulay forces in first-principles simulations using variable basis functions, E-CAM Workshop on Quantum MD, University College Dublin, IE, 2017 Invited Talk, 2017 URL

G. Moynihan, G. Teobaldi, and D. D. O'Regan, The inapplicability of exact constraints, and a minimal two-parameter DFT+U generalisation, for self-interaction error correction, DPG Spring Meeting, Dresden, DE, 2017 Poster, 2017 URL

G. Moynihan, S. Sanvito, and D. D. O'Regan, Strain-induced Weyl and Dirac states and direct- indirect gap transitions in group-V materials, SFI AMBER Centre International Site Review, Dublin, IE, 2017 Poster, 2017

E. Linscott, D. Cole, D. O'Regan, C. Weber, and M. Payne, Electronic Correlation in Biology: advances and applications of linear-scaling DFT, DFT+U, and DMFT, 5th Annual CCP-BioSim Conference: Frontiers of Biomolecular Simulation, Southampton, U.K., 2017 Poster, 2017 URL

G. Moynihan, G. Teobaldi, and D. D. O'Regan, An optimisability proof for self-consistent constrained DFT, and its implications for constraint-based self-interaction error correction, DPG Spring Meeting, Dresden, DE, 2017 Oral Presentation, 2017 URL

D. D. O'Regan and E. Artacho, Diffeogeometric compensation for basis set evolution in quantum atomistic simulations, Irish Quantum Foundations Conference, University College Dublin, IE, 2017 Oral Presentation, 2017 URL

D. D. O'Regan, G. Moynihan, and G. Teobaldi, "Optimizing constraints and corrections in approximate DFT, 17th International Conference on Density-Functional Theory and its Applications, Tällberg, SE, 2017 Oral Presentation, 2017 URL

D. D. O'Regan and N. Marzari, DFT+U(ω): Frequency-dependent Hubbard U correction, Physics Institute, Universidade Federal Fluminense, Niteroí, BR, 2017 Oral Presentation, 2017

A. Lunghi, S. Sanvito, and D. D. O'Regan, Towards multi-scale high-throughput calculations of thermal and mechanical properties in transition-metal alloys, DPG Spring Meeting, Dresden, DE, 2017 Oral Presentation, 2017

D. D. O'Regan, G. Moynihan, O. K. Orhan, E. B. Linscott, and G. Teobaldi, A ground-state tracking linear-response method for the self-consistent Hubbard U applied to oxides, coordination complexes, and excitations, Theory and Simulation of Condensed Matter Seminar, King's College London, London, U.K., 2017 Invited Talk, 2017

D. D. O'Regan, Developments in linear-scaling DFT for theoretical spectroscopy and Mott- Hubbard physics in disordered systems, Workshop on Research Collaboration FAPESP-Trinity, São Paulo, BR, 2017 Oral Presentation, 2017 URL

G. Moynihan, G. Teobaldi, and D. D. O'Regan, Comparison of self-consistent DFT+U approaches via direct minimisation, CECAM Workshop: What about U? - Effects of Hubbard Interactions and Hund's Coupling in Solids, Trieste, IT, 2016 Oral Presentation, 2016 URL

D. D. O'Regan and N. Marzari, DFT+U(ω): Frequency-dependent Hubbard U correction, APS March Meeting, Baltimore, MA, U.S.A., 2016 Oral Presentation, 2016 URL

G. Moynihan, G. Teobaldi, and D. D. O'Regan, Self-consistent calculation of Hubbard U parameters within linear-scaling DFT, APS March Meeting, Baltimore, MA, U.S.A., 2016 Oral Presentation, 2016 URL

O. K. Orhan and D. D. O'Regan, Towards accurate optical spectra of bulk gold via first-principles methods, Irish Atomistic Simulators Meeting, University College Dublin, IE, 2016 Poster, 2016 URL

E. Linscott, D. Cole, D. O'Regan, C. Weber, and M. Payne, Describing Correlation Effects in Biological Systems, Physics by the Lake, Windsor, U.K., 2016 Poster, 2016

E. Linscott, D. Cole, D. O'Regan, C. Weber, and M. Payne, Describing Correlation Effects in Biological Systems, CCP9 Young Researchers Event, York, U.K., 2016 Poster, 2016

D. D. O'Regan, Maintaining stability under orbital optimization in linear-scaling DFT: a long- standing problem addressed using differential geometry, CECAM Workshop: Mathematical and Numerical Analysis of Electronic Structure Models, Roscoff, FR, 2016 Oral Presentation, 2016 URL

G. Moynihan and David D. O'Regan, Electronic and Mechanical Properties of Layered Pnictogen Materials, Irish Atomistic Simulators Meeting, University College Dublin, IE, 2016 Poster, 2016 URL

D. D. O'Regan and N. Marzari, Bandwidth renormalization and satellites in SrVO3 from a minimal DFT+U inspired model, ETSF Workshop on Electronic Excitations, Lund, SE, 2016 Oral Presentation, 2016 URL

D. D. O'Regan, Quantum-mechanical simulation from the atoms up: opportunities and challenges, Dublin University Physical Society, Dublin, IE, 2016 Invited Talk, 2016

D. D. O'Regan and A. M. Delaney, Investigation of the theory of angular momentum used in the quantum mechanical simulation of magneto-optical spectroscopy, Irish Atomistic Simulators Meeting, University College Dublin, IE, 2016 Poster, 2016 URL

G. Moynihan and David D. O'Regan, Electronic and Mechanical Properties of Layered Pnictogen Materials, Psi-k Conference 2015, Donostia-San Sebastián, ES, 2015 Poster, 2015 URL

David D. O'Regan, 'Notes for users of DFT+U(+J) in ONETEP', 2015, - Protocol or guideline, 2015 URL

G. Moynihan and D. D. O'Regan, Ab Initio Simulation of Enhanced Phosphorus-based Nano-composite Materials, ETSF Young Researchers Meeting, Paris, FR, 2015 Poster, 2015

G. Teobaldi, D. D. O`Regan, N. D. Hine, and A. A. Mostofi, Self-consistent projector constrained density functional theory in ONETEP, 249th National Meeting of the American Chemical Society, Denver, CO, U.S.A., 2015 Invited Talk, 2015 URL

D. D. O'Regan and N. Marzari, DFT+U(w): a pragmatic approach for calculating and incorporating dynamical Hubbard U corrections in band-structures and beyond, Materials Theory Group Seminar, Tyndall Institute, Cork, IE, 2015 Invited Talk, 2015

D. Cole, G. Lever, L. Lee, C. Weber, D. D. O'Regan, N. Hine, A. Chin, C.-K. Skylaris, and M. Payne, Applications of Large-Scale Electronic Structure Calculations in Biology, Psi-k Conference 2015, Donostia-San Sebastián, ES, 2015 Oral Presentation, 2015 URL

G. Moynihan and D. D. O'Regan, Ab Initio Simulation of Enhanced Phosphorus-based Nano-composite Materials, International Workshop on Computational Physics and Materials Science, Trieste, IT, 2015 Poster, 2015 URL

O. K. Orhan and D. D. O'Regan, First-principles simulation of optical spectra in gold-based alloys, International Workshop on Computational Physics and Materials Science, Trieste, IT, 2015 Poster, 2015 URL

E. Linscott, D. Cole, D. O'Regan, N. Hine, and M. Payne, Correlation Effects in the Electronic Structure of PSII, Psi-k Conference 2015, Donostia-San Sebastián, ES , 2015 Poster, 2015 URL

O. K. Orhan and D. D. O'Regan, The optical properties of gold and its alloys via GW and TDDFT, Psi-k Conference 2015, Donostia-San Sebastián, ES, 2015 Poster, 2015 URL

D. D. O'Regan and N. Marzari, Frequency-dependent Hubbard U corrections: a viewpoint from density-functional theory, Condensed Matter Theory Group Seminar, University of Warwick, Warwick, UK, 2015 Invited Talk, 2015

G. Moynihan, D. O'Regan, C. Cucinotta, and S. Sanvito, Mechanical Properties of Monolayer Black Phosphorus and the effect of van der Waals Forces, ETSF Young Researchers Meeting, Rome, IT, 2014 Poster, 2014

G. Moynihan, C. Cucinotta, S. Sanvito, and D. D. O'Regan, First Principles Simulation of Monolayer Black Phosphorus, Flatlands: Beyond Graphene, Trinity College Dublin, IE, 2014 Poster, 2014

D. D. O'Regan, Large, strongly-correlated systems simulated with linear-scaling DFT: recent developments and applications from oxides to biology, Irish Atomistic Simulators Meeting, Belfast, NI, 2014 Oral Presentation, 2014

G. Teobaldi, B. J. Morgan, D. D. O'Regan, N. D. M. Hine, and A. A. Mostofi, Subspace-corrected functionals for linear-scaling density functional theory simulation of extended energy storage interfaces, 248th National Meeting of the American Chemical Society, San Francisco, CA, U.S.A., 2014 Oral Presentation, 2014 URL

D. D. O'Regan and N. Marzari, Frequency-dependent Hubbard U corrections to DFT beyond the random-phase approximation, Physics at the Nanoscale Seminar, King's College London, U.K., 2014 Invited Talk, 2014

D. D. O'Regan, Linear-scaling DFT+U and DFT+DMFT or: How I learned to stop worrying and love nonorthogonality, Cecam Workshop: What about U?, Lausanne, CH, 2014 Invited Talk, 2014 URL

D. D. O'Regan, Revisiting a lesser-known idea of Jules Verne, discussed in his 1889 novel "Sans dessus dessous", Dublin University Physical Society, Dublin, IE, 2014 Invited Talk, 2014

G. Moynihan, D. O'Regan, C. Cucinotta, and S. Sanvito, Mechanical Properties of Monolayer Black Phosphorus and the effect of van der Waals Forces , Irish Atomistic Simulators Meeting, Belfast, NI, 2014 Poster, 2014

G. Moynihan, C. Cucinotta, S. Sanvito, and D. D. O'Regan, First Principles Simulation of Monolayer Black Phosphorus, Hermes Summer School, London, U.K., 2014 Poster, 2014

D. D. O'Regan, (Invited) The O'Regan group in Condensed Matter Theory at TCD School of Physics, SFI AMBER Centre launch event and CRANN Research Day, Dublin, IE, 2013 Poster, 2013

G. Teobaldi, D. D. O'Regan, N. D. M. Hine, and A. A. Mostofi, Linear-scaling approaches to charge- and energy-transfer in (extended) photo-electro-chemical interfaces, Donostia International Physics Centre Seminar, Donostia-San Sebastián, ES, 2013 Invited Talk, 2013 URL

D. D. O'Regan and N. Marzari, Frequency-dependent Hubbard U corrections to DFT: A simple approach, 16th International Workshop on Computational Physics and Materials Science: Total Energy and Force Methods, Trieste, Italy, 2013 Poster, 2013

D. D. O'Regan, Modelling dynamically correlated materials in realistic nanostructures: DFT strategies, and linear-scaling approaches, Collaborative Conference on Materials Research (CCMR), Jeju Island, South Korea, 2013 Invited Talk, 2013

D. D. O'Regan and N. Marzari, A new approach to treating dynamically screened interactions in low-energy corrections to density-functional theory, Department of Physics Seminar, University of Fribourg, CH, 2013 Invited Talk, 2013

D. D. O'Regan and N. Marzari, A simplified approach for dynamical Hubbard corrections to DFT, DPG Spring Meeting: Frontiers of Electronic Structure Theory, Regensburg, DE, 2013 Oral Presentation, 2013 URL

D. D. O'Regan and N. Marzari, Simulating correlated electrons in realistic systems: new approaches, School of Physics Seminar, Trinity College Dublin, IE, 2013 Invited Talk, 2013

D. D. O'Regan, Electronic structure simulations in the large scale and correlated-electron regimes, Molecular Foundry Seminar, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S.A., 2013 Invited Talk, 2013

A. A. Mostofi, D. D. O'Regan, L. Andrinopoulos, N. D. M. Hine, and M. C. Payne, Strong correlations and dispersion interactions with non-orthogonal local orbitals", CECAM Workshop on localised orbitals, Cambridge, UK, 2012 Oral Presentation, 2012 URL

Cole, D. J., O'Regan, D. D., Lee, L. P., Chau, P. L., Skylaris, C. K., Payne, M. C., Biomolecular simulation with the linear-scaling DFT code ONETEP, Abstracts of papers of the American Chemical Society, 11th International Biorelated Polymer Symposium / 243rd National Spring Meeting of the American-Chemical-Society (ACS), San Diego, CA, U.S.A. , 243, 2012, pp1 Oral Presentation, 2012

G. Teobaldi, L. J. Hardwick, D. D. O'Regan, N. D. M. Hine, and A. A. Mostofi, Constrained Density Functional Theory in ONETEP, Spring Meeting of the International Society of Electrochemistry, Washington D.C., U.S.A., 2012 Poster, 2012

G. Teobaldi, D. D. O'Regan, N. D. M. Hine, and A. A. Mostofi, Projector self-consistent constrained DFT, CECAM Workshop on localised orbitals, Cambridge, U.K., 2012 Oral Presentation, 2012 URL

D. D. O'Regan, S. M.-M. Dubois, P. Umari, and P. D. Haynes(ed.), Efficient localised orbitals for large systems, strong correlations and excitations, Psi-k Newsletter, Cambridge, U.K., 113, Psi-k Organisation, 2012, 11-24 p Proceedings of a Conference, 2012 URL

D. D. O'Regan, N. D. M. Hine, M. C. Payne, and A. A. Mostofi, A geometrically-motivated approach to optimisation in electronic structure calculations, Numerical Algorithms and High-Performance Computing Group Seminar,, Mathematics Department, EPFL, Lausanne, CH, 2012 Invited Talk, 2012

C. Weber, D. D. O'Regan, N. D. M. Hine, M. C. Payne, G. Kotliar, and P. B. Littlewood, Dynamical mean-field theory applied to linear scaling density functional theory, CECAM Workshop on localised orbitals, Cambridge, U.K., 2012 Oral Presentation, 2012 URL

Y. Fontana, D. D. O'Regan, N. Marzari, A. Fontcuberta i Morral et al., Self-assembled Quantum Dots in Core-Shell Nanowires, NCCR Quantum Science and Technology, Monte Verità, CH, 2012 Poster, 2012

A. Mostofi, D. D. O'Regan, N. D. M. Hine, and M. C. Payne, Linear-scaling DFT+U applied to hole localization and Friedel oscillations in very dilute (Ga,Mn)As, APS March Meeting, Boston, MA, 2012 Oral Presentation, 2012 URL

D. D. O'Regan, N. D. M. Hine, M. C. Payne, and A. A. Mostofi, A linear-scaling DFT+U study of Friedel oscillations and localization in very dilute Gallium Manganese Arsenide, DPG Spring Meeting, Berlin, DE, 2012 Oral Presentation, 2012 URL

D. D. O'Regan, Nonorthogonal Wannier function optimisation: geometric aspects and linear-scaling applications to strongly-correlated materials and spectroscopy, DIPC Seminar, University of the Basque Country, Donostia-San Sebastián, ES, 2011 Invited Talk, 2011 URL

D. D. O'Regan, N. D. M. Hine, M. C. Payne, and A. A. Mostofi, Decorrelating user and theory in ab initio calculations on strongly correlated materials: Projector self-consistent DFT+U for large systems, CECAM Workshop on Materials Informatics, Lausanne, CH, 2011 Invited Talk, 2011 URL

D. D. O'Regan, Optimised projections and tensorial invariance in methods for large and strongly-correlated systems, Materials Modelling Laboratory Seminar, Oxford University, Oxford, UK, 2011 Invited Talk, 2011

S. M.-M. Dubois, L. Ratcliff, D.D. O'Regan et al., Prospects for linear scaling calculations beyond DFT accuracy, CECAM Workshop on GW Calculations for Complex Systems, Lausanne, CH, 2011 Poster, 2011

D. D. O'Regan, N. D. M. Hine, M. C. Payne, and A. A. Mostofi, Projector self-consistent DFT+U with linear-scaling and tensorial invariance, CECAM-ACAM Workshop on Density Functional Theory, University College Dublin, IE, 2011 Poster, 2011

D. D. O'Regan, A. A. Mostofi, and M. C. Payne, Linear-scaling and projector self-consistent DFT+U for electronic correlations in large systems, Thomas Young Centre International Review, University College London, U.K., 2010 Poster, 2010

D. D. O'Regan, Accelerating linear-scaling DFT: Differential geometry meets electronic structure theory, Thomas Young Centre, Imperial College London, U.K., 2010 Invited Talk, 2010

D. D. O'Regan, A. A. Mostofi, and M. C. Payne, Linear-scaling and projector self-consistent DFT+U for electronic correlations in large systems, Psi-k Conference, Berlin, DE, 2010 Poster, 2010

D. D. O'Regan, M. C. Payne, and A. A. Mostofi, Linear-scaling and projector self-consistent DFT+U for electronic correlations in large systems, APS March Meeting, Portland, OR, U.S.A., 2010 Oral Presentation, 2010 URL

D. D. O'Regan, A. A. Mostofi, and M. C. Payne, Linear scaling DFT+U with ONETEP, CCP9 Conference, Cambridge, U.K., 2009 Poster, 2009

D. D. O'Regan, A. A. Mostofi, and M. C. Payne, Wannier functions in the study of strong electronic correlations in DNA, International Workshop on DNA-based nanotechnology, Max-Planck-Institut für Physik komplexer Systeme, Dresden, DE, 2009 Poster, 2009

D. D. O'Regan, A. A. Mostofi, and M. C. Payne, Linear scaling DFT+U with ONETEP, 14th International Workshop on Computational Physics and Materials Science: Total Energy and Force Methods, Trieste, IT, 2008 Poster, 2008

Research Expertise

Keywords

Advanced electronic materials; ATOMISTIC SIMULATION; BIOSCIENCE; CHIROPTICAL SPECTROSCOPY; COMPUTER MODELING AND SIMULATION; CONSTRAINED DENSITY-FUNCTIONAL THEORY; DENSITY-FUNCTIONAL THEORY; DYNAMICAL MEAN-FIELD THEORY; Functional Materials; HARD MAGNETIC MATERIALS; LINEAR-SCALING DENSITY-FUNCTIONAL THEORY; MAGNETIC MATERIALS; MANY-BODY PERTURBATION THEORY; MANY-BODY THEORY; MATERIALS SCIENCE; METALLOPROTEINS; nanoscience; Organometallic Chemistry; REDUCED DENSITY-MATRIX FUNCTIONAL THEORY; SEMICONDUCTOR DEVICES AND MATERIALS; Theoretical Physics; THEORETICAL SPECTROSCOPY; TIME-DEPENDENT DENSITY-FUNCTIONAL THEORY