Oscillatory angular dependence of the magnetoresistance in a topological insulator Bi_{1-x}Sb_{x}

摘要

The angular-dependent magnetoresistance and the Shubnikov-de Haasoscillations are studied in a topological insulator Bi_{0.91}Sb_{0.09}, wherethe two-dimensional (2D) surface states coexist with a three-dimensional (3D)bulk Fermi surface (FS). Two distinct types of oscillatory phenomena arediscovered in the angular-dependence: The one observed at lower fields is shownto originate from the surface state, which resides on the (2\bar{1}\bar{1})plane, giving a new way to distinguish the 2D surface state from the 3D FS. Theother one, which becomes prominent at higher fields, probably comes from the(111) plane and is obviously of unknown origin, pointing to new physics intransport properties of topological insulators.