Quantum oscillations of robust topological surface states up to 50\u2009K in thick bulk-insulating topological insulator

Weiyao Zhao,Zengji Yue,David Cortie,Lei Chen,Zhi Li,Xiaolin Wang,Michael Fuhrer

doi:10.1038/s41535-019-0195-7

Abstract

As personal electronic devices increasingly rely on cloud computing for energy-intensive calculations, the power consumption associated with the information revolution is rapidly becoming an important environmental issue. Several approaches have been proposed to construct electronic devices with low-energy consumption. Among these, the low-dissipation surface states of topological insulators (TIs) are widely employed. To develop TI-based devices, a key factor is the maximum temperature at which the Dirac surface states dominate the transport behavior. Here, we employ Shubnikov-de Haas oscillations (SdH) as a means to study the surface state survival temperature in a high-quality vanadium doped Bi1.08Sn0.02Sb0.9Te2S single crystal system. The temperature and angle dependence of the SdH show that: (1) crystals with different vanadium (V) doping levels are insulating in the 3–300 K region; (2) the SdH oscillations show two-dimensional behavior, indicating that the oscillations arise from the pure surface states; and (3) at 50 K, the V0.04 single crystals (Vx:Bi1.08-xSn0.02Sb0.9Te2S, where x = 0.04) still show clear sign of SdH oscillations, which demonstrate that the surface dominant transport behavior can survive above 50 K. The robust surface states in our V doped single crystal systems provide an ideal platform to study the Dirac fermions and their interaction with other materials above 50 K.

Highlights

Since the concept of topology has been introduced into condensed matter physics, an exotic form of quantum matter, namely, the topological insulator (TI), has attracted much attention, in which there is no transport of electrons in the bulk of the material, while the edges/surface can support metallic electronic states protected by time-reversal symmetry.[1]
We found that the Shubnikov-de Haas oscillations (SdH) oscillations could survive up to 50 K in all three samples, especially clear in the V0.04 sample (Vx:Bi1.08-xSn0.02Sb0.9Te2S, where x = 0.04), which allows 3D TI-based study of this substrate above the 50 K region
Se is widely used as a dopant to tune the band structure, which results in the (Bi,Sb)2(Te,Se)[3] (BSTS) formula for the most popular topological insulator

Summary

Introduction

Since the concept of topology has been introduced into condensed matter physics, an exotic form of quantum matter, namely, the topological insulator (TI), has attracted much attention, in which there is no transport of electrons in the bulk of the material, while the edges/surface can support metallic electronic states protected by time-reversal symmetry.[1]. Most of the known TI materials are not bulk-insulating, which hinders study of the transport properties of the surface states. The new low-energy electronics industry requires wafersize thick topological insulator materials with stable surface states and a large bulk band gap.

Results

Conclusion