Photogalvanic in ultrathin film of topological insulator

In this work, we study the photogalvanic effect on an ultrathin film of topological insulator Bi2Se3 family. we find that there is photocurrent when circularly polarized light shines obliquely on the ultrathin film if there is an asymmetric potential between the two surfaces. There is no current when the light is linearly polarized.