Terahertz wave emission from the trigonal layered PtBi(2)

In this work, broadband terahertz (THz) wave emissions have been detected from the trigonal layered PtBi(2) on the excitation of the femtosecond laser pulses. Such THz generation is found to arise from the dominated linear photogalvanic effect, which is further discovered to strongly depend on the unique electronic structures of PtBi(2). Furthermore, an effective nonlinear susceptibility of PtBi(2) is also obtained and is nearly two orders of magnitude larger than that of the traditional nonlinear crystal for THz generation.