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Title: Spectral dynamics of shift current in ferroelectric semiconductor SbSI
Authors: Sotome, M.Nakamura, M.Fujioka, J.Ogino, M.Kaneko, Y.Morimoto, T.Zhang, Y.Kawasaki, M.Nagaosa, N.Tokura, Y.Ogawa, N.
Publishers Version:
Issue Date: 2019
Published in: Proceedings of the National Academy of Sciences of the United States of America Vol. 116 (2019), No. 6
Publisher: Washington : National Academy of Sciences
Abstract: Photoexcitation in solids brings about transitions of electrons/ holes between different electronic bands. If the solid lacks an inversion symmetry, these electronic transitions support spontaneous photocurrent due to the geometric phase of the constituting electronic bands: the Berry connection. This photocurrent, termed shift current, is expected to emerge on the timescale of primary photoexcitation process. We observe ultrafast evolution of the shift current in a prototypical ferroelectric semiconductor antimony sulfur iodide (SbSI) by detecting emitted terahertz electromagnetic waves. By sweeping the excitation photon energy across the bandgap, ultrafast electron dynamics as a source of terahertz emission abruptly changes its nature, reflecting a contribution of Berry connection on interband optical transition. The shift excitation carries a net charge flow and is followed by a swing over of the electron cloud on a subpicosecond timescale. Understanding these substantive characters of the shift current with the help of first-principles calculation will pave the way for its application to ultrafast sensors and solar cells.
Keywords: Bulk matter; Ferroelectricity; Photovoltaic effect; Picosecond techniques; Solar cells; antimony derivative; antimony sulfur iodide; iodine derivative; sulfur derivative; unclassified drug; Article; dynamics; electric current; electromagnetic radiation; electron transport; factor analysis; ferroelectric semiconductor; mathematical computing; photon; priority journal; terahertz radiation
DDC: 530
License: CC BY-NC-ND 4.0 Unported
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