Friday, February 5, 2016
Abstract-Surface and interface states of Bi2Se3 thin films investigated by optical second-harmonic generation and terahertz emission
We investigate the and interface states of BiSe thin films by using the second-harmonic generation technique. Distinct from the of bulk crystals, the film and interface show the isotropic azimuth dependence of second-harmonic intensity, which is attributed to the formation of randomly oriented domains on the in-plane. Based on the nonlinear susceptibility deduced from the model fitting, we determine that the band bending induced in a space charge region occurs more strongly at the film interface facing the AlO substrate or capping layer compared with the interface facing the air. We demonstrate that distinct behavior of the terahertz emitted from the samples can provide further information about the electronic state of BiSe.