Figure 4: Mechanism of zero-bias photocurrent generation.
From: Zero-bias photocurrent in ferromagnetic topological insulator
Schematics for the energy dispersion in the magnetic topological insulator for the out-of-plane Sz (a) and in-plane Sy (b,c) alignment of dopant spin. Corresponding energy contours calculated from equation (1) are depicted in (d,e). Possible imbalance in the photoexcitation at the opposite kx is shown in b: grey and orange arrows for low- and high-photon-energy excitations, respectively. The scattering between the surface and bulk states is shown in c.
