Detection of Surface States in Bi_2 – xSb_xTe_3 – ySe_y Topological Insulators by Magnetotransport Measurements

In this paper, we studied the effect of the magnetic field and temperature on conductivity of Bi_2 ‒ xSb_xTe_3 – ySe_y topological insulators of different composition to identify electronic surface states in these films. The experimental data can be explained based on the model with two types of charge carriers. Thermoactivation conductivity, electron or hole, is observed in the film bulk depending on the sample composition while metal-like electronic states are found on the surface. The noticeable contribution of surface topological states to the total conductivity opens up the possibility of studying them.