Surface states induced weak anti-localization effect in Bi0.85Sb0.15 topological single crystal

TL;DR

This study provides experimental evidence of surface state-driven weak anti-localization in Bi0.85Sb0.15 single crystals, revealing high magnetoresistance and multiple conduction channels through detailed magneto-transport measurements and analysis.

Contribution

It is the first detailed magneto-transport study demonstrating surface state effects and weak anti-localization in Bi0.85Sb0.15 single crystals, with comprehensive analysis of scattering mechanisms.

Findings

Non-saturating magnetoresistance of 4250% at 2K and 12T

Observation of weak anti-localization effect near zero magnetic field

Confirmation of surface state dominated transport through angle-dependent measurements

Abstract

We report, an experimental evidence of surface states (SS) driven magneto-transport in a Bi0.85Sb0.15 single crystal. Detailed high field (up to 12T) and low temperature (down to 2K) magneto-transport measurements are been carried out on the studied Bi0.85Sb0.15 single crystal. The phase, composition and Raman modes are studied through X-ray diffraction, Energy dispersive X-ray, and Raman spectroscopy. The obtained crystal shows non-saturating magnetoresistance (4250%) at 2K and 12T, along with the existence of weak-anti localization (WAL) effect at around zero magnetic field. Further, the Hikami-Larkin-Nagaoka (HLN) analysis is performed to analyse the WAL effect. The prefactor and phase coherence length are deduced at various temperatures, which signified the presence of more than one conduction channel in the studied Bi0.85Sb0.15 single crystal. The effect of quantum scattering, bulk contribution from underneath the surface states and defects are been studied by adding various field dependent quadratic, linear and constant terms to the SS driven HLN equation. Various possible scattering mechanism are studied by analysing the temperature dependence of the phase coherence length. Angle dependent magneto-conductivity of the studied Bi0.85Sb0.15 single crystal clearly confirmed the surface states dominated transport in present crystal.