Oscillating planar Hall response from the surface electrons in bulk crystal Sn doped Bi1.1Sb0.9Te2S

TL;DR

This study investigates the surface electron transport in a bulk topological insulator crystal, revealing oscillating planar Hall effects that serve as a new criterion for topological surface conduction.

Contribution

It demonstrates the emergence of oscillating planar Hall effects in bulk topological insulators, establishing a new diagnostic criterion for surface state transport.

Findings

Planar Hall oscillations depend on magnetic field orientation.

Oscillation amplitude peaks at low temperatures.

Oscillations diminish above 100 K.

Abstract

We report the low-temperature magneto-transport in the bulk-insulating single crystal of topological insulator Sn doped Bi1.1Sb0.9Te2S. The Shubnikov-de Haas oscillations appear with their reciprocal frequency proportional to cos/theta , demonstrating the dominant transport of topological surface states. While the magnetic field is rotating in the sample surface, the planar Hall effect arises with sizeable oscillations following a relation of cos/theta sin/theta . Its amplitude reaches the maximum at the lowest temperature and drops to nearly zero at the temperature higher than 100 K. All these evidences consolidate such planar Hall oscillations as a new golden criterion on the topological surface transport.