Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 62: Electronic-Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond - V
HL 62.1: Talk
Wednesday, March 22, 2017, 15:00–15:15, GER 38
First-principle Linear Response in Real Space — •Honghui Shang1, Danilo S. Brambila1, Christian Carbogno1, Patrick Rinke2, and Matthias Scheffler1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin — 2Aalto University, Helsinki, Finland
Density-functional perturbation theory (DFPT) has developed into an important computational tool for assessing the linear electronic response of crystalline solids to perturbations, e.g., from electric fields or nuclear displacements [1]. In this work we present a full real-space reformulation of DFPT and its implementation [2] in the all-electron, numeric atom-centered orbital electronic structure theory code FHI-aims. We discuss the specific contributions, e.g., relativistic effects and Pulay terms, that arise in such a formulation and validate our implementation by systematically comparing with the finite-difference approach for various extended systems. The computational efficiency is then analyzed via scaling and scalability tests on massively parallel architectures (CRAY and IBM x86 clusters). Finally, we show that this real-space formalism enables an arbitrarily dense sampling of the Brillouin zone by numerically cheap Fourier transformations, which in turn facilitates an efficient evaluation of the electron-phonon coupling matrix elements. We demonstrate the efficiency by computing the relaxation time of hot carriers in Si.
[1] X. Gonze and C. Lee, Phys. Rev. B 55, 10355, (1997).
[2] H. Shang, et al., Comp. Phys. Comm. (accepted), arXiv:1610.03756.