Shift charge and spin photocurrents in Dirac surface states of topological insulator
* SPEAKERS
Name
Affiliation
E-mail
Kun Woo Kim
KIAS
* HOST(Applicant)
Name
Affiliation
E-mail
Jae Yoon Cho
APCTP
* DATE / TIME
2016-07-26, 16:00~
* PLACE
512 Seminar room, APCTP, Hogil Kim Memorial Building, POSTECH
* ABSTRACT
The generation of photocurrent in condensed matter is of main interest for photovoltaic and optoelectonic 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 Bi_2X_3 (X: Te, Se), we find that Dirac surface states with hexagonal warping term carry shift current by linearly polarized light. In addition, shift spin-current is introduced with the time-reversal symmetry breaking perturbation. The estimate for the magnitudes of the shift charge- and spin-currents are 0.13 I_0 and 0.21 I_0(nA/m) with the intensity of light I_0 measured in (W/m^2) respectively, which can offer a useful method to generate these currents efficiently.
