Phonon-Assisted Ballistic Current from First-Principles Calculations
ORAL
Abstract
The bulk photovoltaic effect (BPVE) refers to current generation due to illumination by light in a homogeneous bulk material lacking inversion symmetry. In addition to the intensively studied shift current, the ballistic current, which originates from asymmetric carrier generation due to scattering processes, also constitutes an important contribution to the overall kinetic model of the BPVE. In this work, we use a perturbative approach to derive a formula for the ballistic current resulting from the intrinsic electron-phonon scattering in a form amenable to first-principles calculation. We then implement the theory and calculate the ballistic current of the prototypical BPVE material BaTiO3 using quantum-mechanical density functional theory. The magnitude of the ballistic current is comparable to that of the shift current, and the total spectrum (shift plus ballistic) agrees well with the experimentally measured photocurrents. Furthermore, we show that the ballistic current is sensitive to structural change, which could benefit future photovoltaic materials design.
*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-FG02-07ER46431. L. Z. T. was supported by the Molecular Foundry, a DOE Office of Science User Facility funded by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02- 05CH11231. Computational support was provided by the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy, Office of Science User Facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02-05CH11231.
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Publication:Z. Dai, A. N. Schankler, L. Gao, L. Z. Tan and A. M. Rappe. Phonon-Assisted Ballistic Current from First-Principles Calculations. Physical Review Letters 126, 177403 (2021). DOI: 10.1103/PhysRevLett.126.177403
