SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 79: Focus Session: Frontiers of Electronic-Structure Theory VI (joint session O/HL)

O 79.4: Vortrag

Donnerstag, 30. März 2023, 11:45–12:00, TRE Ma

Fully Anharmonic Electronic Transport Coefficients from Temperature-dependent Spectral Functions — •Jingkai Quan, Matthias Scheffler, and Christian Carbogno — The NOMAD Laboratory at the FHI of the Max-Planck-Gesellschaft and IRIS-Adlershof of the Humboldt-Universität zu Berlin

The combination of ab initio molecular dynamics (aiMD) and band-structure unfolding techniques provides a non-perturbative route to obtain temperature-dependent spectral functions. [1] In contrast to commonly employed perturbative approaches [2], this technique accounts for all orders of anharmonic and vibronic couplings. Building on this non-perturbative formalisms, we here present an approach to obtain electronic transport coefficient such as the electrical conductivity using Kubo’s formulation of the fluctuation-dissipation theorem. By this means, all relevant quantities, including electron lifetimes, are obtained from the unfolded, self-consistent wave functions computed during the aiMD runs. We critically benchmark the approach against existing perturbative data for harmonic systems, carefully analyzing to which extent short- and long-range couplings are captured with increasing supercell size. Furthermore, we demonstrate the advantages of the proposed approach for strongly anharmonic systems, for which perturbative approaches become unreliable.

[1] M. Zacharias, M. Scheffler, and C. Carbogno, Phys. Rev. B 102, 045126 (2020).

[2] F. Giustino, Rev. Mod. Phys. 89, 015003 (2017).