Accessing topological surface states and negative MR in sculpted nanowires of Bi2Te3 at ultra-low temperature

TL;DR

This study demonstrates the observation of topological surface states and negative magnetoresistance in sculpted Bi2Te3 nanowires at ultra-low temperatures, revealing quantum transport phenomena and the coexistence of surface and bulk conduction.

Contribution

It provides experimental evidence of topological surface state transport in nanowires fabricated by milling, analyzed through magnetoconductivity and WAL effects at millikelvin temperatures.

Findings

Observation of weak antilocalization effects at ultra-low temperatures.

Detection of positive and negative magnetoresistance crossover.

Linear magnetoresistance at 2 K indicating coexistence of surface and bulk transport.

Abstract

Milling of 2D flakes is a simple method to fabricate nanomaterial of any desired shape and size. Inherently milling process can introduce the impurity or disorder which might show exotic quantum transport phenomenon when studied at the low temperature. Here we report temperature dependent weak antilocalization (WAL) effects in the sculpted nanowires of topological insulator in the presence of perpendicular magnetic field. The quadratic and linear magnetoconductivity (MC) curves at low temperature indicate the bulk contribution in the transport. A cusp feature in magnetoconductivity curves (positive magnetoresistance) at ultra low temperature and at magnetic field, less than 1T represent the WAL indicating the transport through surface states. The MC curves are discussed by using the 2D Hikami Larkin Nagaoka theory. The crossover interplay nature of positive and negative magnetoresistance observed in the MR curve at ultra low temperature. Our results indicate that transport through topological surface states (TSS) in sculpted nanowires of Bi2Te3 can be achieved at mK range and linear MR observed at 2 K could be the coexistence of electron transport through TSS and contribution from the bulk band.