Fig. 3
From: Spin Hall photoconductance in a three-dimensional topological insulator at room temperature
Helicity vs. bias and facet dependence of helical photoconductance. a, b Sketch of a BTS platelet with dark current j along the x-direction, when a bias Vsd is applied. The current defines the direction of the electron wave vector kelectron at the left and right edge. The electron spin-polarization S is perpendicular to kelectron and points in opposite directions at the two edges. In a [b], the left [right] edge is excited with a circularly polarized light with the photon wave vector kphoton pointing downwards. c–e ΔGhelical vs. the laser helicity at the left edge for Vsd = + 1 V (c), 0 V (d), and –1 V (e). The polarization is tuned with a quarter waveplate for an excitation scheme as sketched in a). f-h Similar data for the right edge for an excitation scheme as sketched in b. All measurements are performed at Plaser = 230 µW and room temperature
