Weak Antilocalization and Universal Conductance Fluctuations in Bismuth Telluro-Sulfide Topological Insulators

TL;DR

This paper demonstrates the growth and characterization of Bismuth Telluro-Sulfide nanosheets, revealing their topological surface states through magnetotransport experiments showing weak antilocalization and conductance fluctuations.

Contribution

It introduces a simple growth method for BTS nanosheets and provides detailed magnetotransport analysis confirming their topological insulator properties.

Findings

Observation of weak antilocalization in BTS nanosheets

Identification of surface and bulk conduction channels

Evidence of multiple conducting channels in magnetotransport data

Abstract

We report on van der Waals epitaxial growth, materials characterization and magnetotransport experiments in crystalline nanosheets of Bismuth Telluro-Sulfide (BTS). Highly layered, good-quality crystalline nanosheets of BTS are obtained on SiO$_2$ and muscovite mica. Weak-antilocalization (WAL), electron-electron interaction-driven insulating ground state and universal conductance fluctuations are observed in magnetotransport experiments on BTS devices. Temperature, thickness and magnetic field dependence of the transport data indicate the presence of two-dimensional surface states along with bulk conduction, in agreement with theoretical models. An extended-WAL model is proposed and utilized in conjunction with a two-channel conduction model to analyze the data, revealing a surface component and evidence of multiple conducting channels. A facile growth method and detailed magnetotransport results indicating BTS as an alternative topological insulator material system are presented.