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Quantum Theory of Materials seminar, PGI-1/IAS-1

Dr. Julen Ibanez Azpiroz

Ab initio calculation of the shift photocurrent by Wannier interpolation

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11 Sep 2018 11:30
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PGI Lecture Hall

Materials Physics Center, Donostia-San Sebastian, Spain

Abstract:

The bulk photovoltaic effect (BPVE), also known as the shift-current effect, is a nonlinear optical response that yields a net photocurrent in noncentrosymmetric crystals. Although the theory of the BPVE is well established, its practical implementation is challenging because it involves a subtle Berry-phase-like quantity. Here we present a Wannier-interpolation scheme for the ab-initio calculation of the BPVE, which provides several advantages over previous numerical schemes. On the technical side, it avoids truncation errors and allows for an efficient interpolation of the Brillouin-zone integrand onto a fine k-point mesh, providing high accuracy and convergence. From the physical point of view, it provides a transparent connection to tight-binding approaches that are widely used in the literature, and hence it serves to estimate their accuracy. In the talk, we will bench mark the formalism to calculate the BPVE in bulk GaAs as well as in monolayer GeS, and briefly discuss how to use its implemented version in the WANNIER90 software package.

Contact

Prof. Dr. Samir Lounis
Phone: +49 2461 61-4068
Fax: +49 2461 61-2850
email: s.lounis@fz-juelich.de