Quantum Oscillations of Robust Topological Surface States up to 50 K in Thick Bulk-insulating Topological Insulator

TL;DR

This study demonstrates that topological surface states in V-doped Bi-based topological insulators exhibit quantum oscillations up to 50 K, indicating robust surface conduction at relatively high temperatures for potential device applications.

Contribution

The paper provides experimental evidence of surface state quantum oscillations persisting up to 50 K in V-doped Bi-based topological insulators, highlighting their robustness.

Findings

SdH oscillations show 2D surface state behavior

Surface states survive above 50 K in V0.04 crystals

Doped crystals remain insulating from 3-300 K

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.