Shift charge and spin photocurrents in Dirac surface states of topological insulator

초록

The generation of photocurrent in condensed matter is of main interest for photovoltaic and optoelectronic applications. Shift current, a nonlinear photoresponse, has attracted recent intensive attention as a dominant player of bulk photovoltaic effect in ferroelectric materials. In three-dimensional topological insulators Bi2X3 (X=Te, Se), we find that Dirac surface states with a hexagonal warping term support shift current by linearly polarized light. Moreover, we study shift spin current that arises in Dirac surface states by introducing time-reversal symmetry breaking perturbation. The estimate for the magnitudes of the shift charge and spin current densities are 0.13I0 and 0.40I0 (nA/m) for Bi2Te3 with the intensity of light I0 measured in (W/m2), respectively, which can offer a useful method to generate these currents efficiently. © 2017 American Physical Society.

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