Fig. 2
From: Spin Hall photoconductance in a three-dimensional topological insulator at room temperature
Irradiance dependence of helical and polarization-independent photoconductance. a The helical ΔGhelical is linear up to the largest laser powers investigated, and can be tuned to be positive or negative. The polarity depends on the excitation position and the direction of the dark current in the platelets. We show ΔGhelical for a right edge of a BTS platelet at a positive bias Vsd = + 0.55 V. b The polarization-independent photoconductance Gphoto of the BTS platelets shows a non-linear power dependence. The non-linearity is an interplay of saturating photoconductance contributions of the surface and bulk states of the BTS platelet (saturating for Plaser ≥ 5 mW) and a negative bolometric photoconductance dominating at large laser powers [cf. ref. 12]. All measurements are performed at room temperature
