Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 52: Focus Session: Electron-Phonon Interactions I

O 52.7: Vortrag

Mittwoch, 3. April 2019, 12:30–12:45, H15

Fully-Anharmonic, First-Principles Theory of Electronic Transport — •Zhenkun Yuan, Marios Zacharias, Matthias Scheffler, and Christian Carbogno — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin

Under typical operation conditions, thermoelectric charge and heat transport are limited by scattering events resulting from electron-phonon coupling (EPC). Although much progress has been made in assessing the respective electronic transport coefficients in the harmonic approximation [1], recent evidence suggests that anharmonic contributions both in the nuclear motion and the EPCs can play a decisive whereas typically ignored role [2]. We here present a first-principles formalism that fully accounts for these anharmonic effects in electronic transport: Anharmonicity in the nuclear motion is accounted for via ab initio molecular dynamics, while anharmonicity in the EPCs is included by evaluating the electronic self-energy along these trajectories in a real-time density-matrix formalism. This gives access to the electronic charge and heat fluxes, enabling us to obtain the thermoelectric transport coefficients via the fluctuation-dissipation theorem. Using both harmonic elemental semiconductors and anharmonic perovskites as example, we discuss the advantages and challenges of the proposed approach.