Modeling of Magneto-Conductivity of Bismuth Selenide -- A Topological Insulator

TL;DR

This paper develops a new model to accurately describe the magneto-conductivity of Bi2Se3 topological insulator crystals across various temperatures and magnetic fields, addressing limitations of existing models.

Contribution

It introduces a combined model incorporating surface-driven HLN and classical bulk contributions, improving fit to experimental data at high magnetic fields.

Findings

Magnetoresistance of 380% at 14T and 5K

HLN model deviates at fields above 1T

Proposed model fits data from 5K to 200K and up to 14T

Abstract

We report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of 14Tesla. 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 percent at a magnetic field of 14T and a temperature of 5K. 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 Tesla, 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 to 200K) and applied magnetic fields (up to 14Tesla).