Photo-excited terahertz response of topological insulator Sb 2 Te 3

By employing ultrafast time-resolved optical pump terahertz (THz) probe spectroscopy, we report a comparative THz response on CVD grown topological insulator (TI) Sb 2 Te 3 under different temperatures. Both photo induced carrier dynamics attributed to the surface and bulk electrons are observed. The electron system undergoes an ultrafast excitation and relaxation and releases through intra-band and inter-band scattering.