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:

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:

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: