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O: Fachverband Oberflächenphysik

O 70: Poster Session V: Poster to Mini-Symposium: Frontiers of electronic-structure theory II

O 70.4: Poster

Mittwoch, 3. März 2021, 10:30–12:30, P

Non-Perturbative Theory of Charge Transport in Crystalline Solids — •Christian Carbogno and Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft

Our understanding of charge transport in crystalline solids predominantly relies on the Boltzmann transport equation. However, its perturbative approximations for the nuclear dynamics and for its coupling to the electrons can be inaccurate in complex materials [1]. We present an alternative, non-perturbative ab initio Green-Kubo approach based on a new formulation of the flux viz. polarization. It can be evaluated via ab initio molecular dynamics and only requires gauge-fixed properties. At variance with Berry phase approaches [2], it can thus be evaluated for (semi-)conductors at finite temperatures featuring thermal electronic excitations. We demonstrate our methodology by calculating the electrical conductivity for 2D honeycomb lattices as well as for the harmonic material Si and the anharmonic perovskite SrTiO₃. Furthermore, we systematically compare to non-perturbative Kubo-Greenwood calculations and discuss why the latter approach has so far only been numerically applicable for materials with strong structural disorder [3], i.e., when the dispersion in reciprocal space is negligible.

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

[2] R. D. King-Smith and D. Vanderbilt, Phys. Rev. B 47, 1651 (1993).

[3] B. Holst, M. French, and R. Redmer, Phys. Rev. B 83, 235120 (2011); C. Di Paola, et al., Phys. Rev. Research 2, 033055 (2020).