Modeling of magneto-conductivity of bismuth selenide: a topological insulator

Yogesh Kumar,V P S Awana,Prince Sharma,Rabia Sultana

doi:10.1007/s42452-021-04397-8

Abstract

We report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

Highlights

Topological insulators have gained tremendous attention in recent years due to helical spin texture exhibiting vital quantum transport phenomena [1, 2]
To investigate this, the physical significance of MC is thoroughly explored by dividing the MC into two different regions, such as a region of surface states that lies from low field to 1 T only and another one is the elastic/spin–orbit scattering and classical contribution states which lies from 1 T to high fields
We concluded that magneto-conductivity of B i2Se3 single crystals at different temperatures for a magnetic field range of ± 14 T could be modeled by considering the contributions from surface-driven states, quantum scatterings, and the bulk

Summary

Introduction

Topological insulators have gained tremendous attention in recent years due to helical spin texture exhibiting vital quantum transport phenomena [1, 2]. With an increase in L φ, quantum enhancement is added to classical electronic conductivity, leading to topological delocalization or Weak anti-localization effect (WAL) [14, 15]. It is considered as a hallmark for topological surface states (SSs) and is expected to be in systems with simplistic symmetry [16]. We find that these quadratic term does not appropriately account for the MC in our case as apart from these quantum scatterings, there is a possible role of bulk carriers that comes into the picture at higher temperatures and applied magnetic fields. It is shown that two-dimensional transport features may not always originate from the surface states alone in Bi-based topological insulators

Experimental details

Results and discussion

Conclusion