First-principles calculation of ballistic photocurrents
ORAL
Abstract
The bulk photovoltaic effect (BPVE) is the generation of photocurrents in crystals with broken inversion symmetry. Ballistic currents, which arise from asymmetric phonon scattering, and shift currents, which are displacements of electrons upon photoexcition, have been proposed as mechanisms responsible for the BPVE under linearly polarized light. However, only the shift current contribution has been routinely studied with first-principles calculations. In this work, we present first-principles calculations of the phonon-induced ballistic current contribution. These ballistic currents arise from an unbalanced momentum space distribution of carriers, which results from the interference of multiple carrier-phonon scattering processes. We calculate the amplitudes of these processes using electron-phonon interactions derived from density functional pertubation theory, to find the carrier distribution functions and the magnitudes of ballistic photocurrents. We apply this methodology to BaTiO3, a typical ferroelectric which displays the BPVE. These results clarify the origin of the BPVE, and the relative importance of shift and ballistic currents.
–
Presenters
-
Liang Tan
Department of Chemistry, University of Pennsylvania, Lawrence Berkeley National Laboratory, Molecular Foundry, Lawrence Berkeley National Laboratory, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley
Authors
-
Liang Tan
Department of Chemistry, University of Pennsylvania, Lawrence Berkeley National Laboratory, Molecular Foundry, Lawrence Berkeley National Laboratory, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley
-
Ruixiang Fei
Department of Chemistry, University of Pennsylvania, University of Pennsylvania
-
Andrew Rappe
University of Pennsylvania, Department of Chemistry, University of Pennsylvania, Chemistry, University of Pennsylvania