Surface Shubnikov–de Haas oscillations and nonzero Berry phases of the topological hole conduction in Tl{1−x}Bi{1+x}Se{2}

Abstract

We report the observation of two-dimensional Shubnikov–de Haas (SdH) oscillations in the topological insulator Tl{1−x}Bi{1+x}Se{2}. Hall effect measurements exhibited electron-hole inversion in samples with bulk insulating properties. The SdH oscillations accompanying the hole conduction yielded a large surface carrier density of ns=5.1×10(12) cm(−2), with the Landau-level fan diagram exhibiting the π Berry phase. These results showed the electron-hole reversibility around the in-gap Dirac point and the hole conduction on the surface Dirac cone without involving the bulk metallic conduction.