Electronic structure and linear magnetoresistance of the gapless topological insulator PtLuSb

The present work reports on the experimental investigation of electronic structure and transport properties of the proposed topological insulator PtLuSb. The electronic structure was investigated by means of polarization dependent hard x-ray photoelectron spectroscopy. The valence band spectra exhibit a linear behavior close to the Fermi energy, as is typical for massless electrons. The transport properties are similar to that of a gapless semiconductor with low carrier concentration. This compound also exhibits an exceptionally high Hall mobility. At low temperatures, the magnetoresistance changes linearly with the applied magnetic field, whereas it exhibits a quadratic nature at high temperatures. A tentative relation between linear magnetoresistance and high mobility is discussed.