David O’Regan

Assit Prof David O’Regan’s research is dedicated to the development and application of novel, accurate, but computationally tractable methodology for atomistic electronic structure simulations, both of solid state materials and molecular systems.

I focus on the interface between techniques for treating large length-scales, the strong electronic correlations almost ubiquitous in systems of technological interest, and theoretical spectroscopy. I am actively involved in the development of linear-scaling density functional theory. Here, I implement and improve corrective approaches such as DFT+U, constrained DFT and DFT+DMFT, as well as researching new Wannierisation and time propagation (TDDFT) algorithms. I maintain a long-term programme in the development of tractable and easily-used methods moving beyond Kohn-Sham DFT, via the density-matrix and Green’s function, not only for spectra but for energies and their derivatives. I’m interested in multiferroic 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. At present, applications of these materials to new high-density energy and data-storage technologies are receiving some attention. I collaborate extensively with leading scientists from diverse fields including nanostructure fabrication, high-performance computing, and condensed matter theory.