Academic CentreLAPW
Linearised augmented plane waves (LAPW) is an all-electron method for performing electronic structure calculations within density-functional theory and many-body perturbation theory. Owing to a small number of numerical approximations, LAPW is informally known as the gold standard for solid-state applications. We develop and implement new approaches and algorithms within the LAPW framework with the goal to attain high precision and improve the scaling of the computational effort.
Our developments are carried out in the code exciting which supports a broad functionality.
Selected publications:
- A. Gulans, S. Kontur, C. Meisenbichler, D. Nabok, P. Pavone, S. Rigamonti, S. Sagmeister, U. Werner, and C. Draxl, exciting — a full-potential all-electron package implementing density-functional theory and many-body perturbation theory, J. Phys.: Condens. Matter 26, 363202 (2014);
- A. Gulans, A. Kozhevnikov, and C. Draxl, Microhartree precision in density functional theory calculations, Phys. Rev. B 97, 161105(R) (2018);
- D. Zavickis, K. Kacars, J. Cīmurs, and A. Gulans, Adaptively compressed exchange in LAPW, arXiv:2201.10914.
Many-body perturbation theory
Many-body perturbation theory applied to the electronic structure is a toolbox of methods for advancing from a mean-field description (as in DFT and the Hartree-Fock approximation) to a correlated picture. These methods enable realistic simulations of electronic excitations via the GW approximation and the Bethe-Salpeter equation. Our present activities are directed towards exploring low-scaling algorithms while retaining the high precision of the LAPW method.
Selected publications:
- T. Björkman, A. Gulans, A. V. Krasheninnikov, and R. M. Nieminen, van der Waals Bonding in Layered Compounds from Advanced Density-Functional First-Principles Calculations, Physical Review Letters, 108, 235502 (2012);
- Andris Gulans, Towards numerically accurate many-body perturbation theory: Short-range correlation effects, The Journal of Chemical Physics, 141, 164127 (2014);
- Dmitrii Nabok, Andris Gulans, and Claudia Draxl, Accurate all-electron G0W0 quasiparticle energies employing the full-potential augmented plane-wave method, Physical Review B, 94, 035118 (2016).
Relativity in DFT calculations
Relativistic effects have an impact on chemical bonds and electronic structure. They therefore must be accounted for in DFT simulations at least for heavy elements. We study and implement approximations required for describing scalar-relativistic effects and the spin-orbit interaction.
Selected publications:
- A. Gulans, and C. Draxl, Influence of spin-orbit coupling on chemical bonding, arXiv:2204.02751.
