Detection of surface electron states in topological insulators (Bi1−xInx)2Se3 using laser terahertz radiation

In this work, we show that the use of terahertz laser radiation combined with magnetic field may be an effective tool for detection of topological surface states which is demonstrated for the case of (Bi$_{1−x}$In$_x$)2Se$_3$ solid solutions being either in topological (x < 0.05) or trivial (x > 0.06) phase. It is revealed that for the topological phase, the photoelectromagnetic effect amplitude is defined by the number of incident radiation quanta, whereas for the trivial phase, it depends on the power of a laser pulse irrespective of its wavelength.