Observation of ultrahigh mobility surface states in a topological crystalline insulator by infrared spectroscopy

Abstract

Probing optical and transport properties of the surface states in topological crystalline insulators remains a challenge. Here, Wang et al. demonstrate that the far-infrared conductivity of Pb1−x Sn x Se (x = 0.23−0.25) single crystals is dominated by the surface states where carriers show a high surface mobility of 40,000 cm2 V−1 s−1.