Low-temperature magnetoresistance hysteresis in Vanadium-doped Bi$_{2}$Te$_{2.4}$Se$_{0.6}$ bulk topological insulators

TL;DR

This study investigates low-temperature magnetoresistance hysteresis in Vanadium-doped Bi2Te2.4Se0.6 topological insulators, revealing how bulk and surface state contributions influence magnetic response and spin-dependent scattering.

Contribution

It demonstrates how Vanadium doping levels affect the dominance of bulk versus surface states in magnetoresistance hysteresis in topological insulators.

Findings

Hysteresis is enhanced when both bulk and surface states contribute to transport.

Hysteresis is suppressed when surface states dominate transport.

Magnetoresistance hysteresis depends on doping level and magnetic field sweep rate.

Abstract

Bi$_{2}$Te$_{2.4}$Se$_{0.6}$ single crystals show gapless topological surface states and doping ($x$) with Vanadium allows to shift the chemical potential in the bulk band gap. Accordingly, the resistivity, carrier density, and mobility are constant below 10 K and the magnetoresistance shows weak antilocalization as expected for low-temperature transport properties dominated by gapless surface states of so-called three-dimensional topological "insulators". However, the magnetoresistance also shows a hysteresis depending on the sweep rate and the magnetic field direction. Here, we provide evidence that such magnetoresistance hysteresis is enhanced if both three-dimensional bulk states and quasi-two-dimensional topological states contribute to the transport ($x$ = 0 and 0.03), and it is mostly suppressed if the topological states govern transport ($x$ = 0.015). The results are discussed in terms of spin-dependent scattering between the different available states