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DS: Fachverband Dünne Schichten

DS 5: Frontiers in Electronic-Structure Theory - Focus on Electron-Phonon Interactions I (joint session O/CPP/DS/HL)

DS 5.1: Hauptvortrag

Montag, 16. März 2020, 10:30–11:00, GER 38

Predominance of non-adiabatic effects in zero-point renormalization of electronic energies. — •Xavier Gonze^1,2, Anna Miglio¹, Véronique Brousseau-Couture³, Gabriel Antonius^4,5, Yang-Hao Chan⁴, Steven Louie⁴, Giantomassi Matteo¹, and Michel Côté³ — ¹UCLouvain, Belgium. — ²Skoltech, Moscow, Russia. — ³Dept. Physique, U. Montréal, Canada. — ⁴Dept. Physics, U. California Berkeley & Materials Sci. Div. NBNL Berkeley, CA, USA. — ⁵Dept. Chim., Bio. & Physique, U. Québec Trois-Rivières, Canada.

Electron-phonon interaction induces variation of bandgaps with temperature, and zero-point motion renormalization (ZPR) even at 0K. Ignored in most calculations, ZPR has been evaluated recently for several materials, often relying on the adiabatic approximation, reasonably valid for materials without infrared (IR) activity, but eagerly applied to other materials. We present the first large-scale (29 materials) first-principles evaluation of ZPR beyond the adiabatic approximation [1]. For materials with light elements the ZPR is often larger than 0.3 and up to 1.1 eV: it is useless to go beyond G0W0 without including ZPR in such materials. For IR-active materials, global agreement with experimental data is obtained only with nonadiabatic effects. They even dominate ZPR for many materials. A generalized Fröhlich model that represents accurately nonadiabatic effects accounts for more than half the ZPR for a large set of materials.

[1] A. Miglio, V. Brousseau-Couture, G. Antonius, Y.-H. Chan, S.G. Louie, M. Giantomassi, M. Côté, and X. Gonze. Submitted.