# Regensburg 2019 – wissenschaftliches Programm

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# DS: Fachverband Dünne Schichten

## DS 6: Frontiers of Electronic-Structure Theory: Focus on the Interface Challenge II (joint session O/CPP/DS/TT)

### DS 6.7: Vortrag

### Montag, 1. April 2019, 16:30–16:45, H9

**Accelerating ***GW*** Calculations within the LAPW Framework** — •Sven Lubeck, Andris Gulans, and Claudia Draxl — Humboldt-Universität zu Berlin, Germany

The *GW* approach of many-body perturbation theory is an indispensable method for calculating the electronic band structure of solids.
Its implementation in computer programs using the linearized augmented plane-wave + local orbital (LAPW+LO) method allows for obtaining numerically precise results. Unfortunately, high precision comes at the price of a large number of LAPWs and LOs.
In this work, we accelerate *GW* calculations by optimizing the use of LAPWs and LOs in the computer package `exciting` [1].
On the one hand, we introduce a systematic way of obtaining a minimal set of LOs. On the other hand, we perform a basis transformation from the plane-wave part of the LAPWs to different types of basis functions, exploring the efficiency of numeric atom-centered orbitals, Gaussian type orbitals, and Kohn-Sham orbitals.
Presenting band gaps of two exemplary materials, zincblende ZnO and hexagonal monolayer BN, we illustrate that our optimization schemes reduce the computational cost down to values as low as 15% without compromising the precision.

[1] A. Gulans, S. Kontur, C. Meisenbichler, D. Nabok, P. Pavone, S. Rigamonti, S. Sagmeister, U. Werner, and C. Draxl, J. Phys.: Condens. Matter **26**, 363202 (2014).