Coexistence of surface and bulk state and negative magnetoresistance in Sulfur doped Bi2Se3

TL;DR

This study investigates how sulfur doping in Bi2Se3 affects its magnetoresistance, revealing a transition to negative MR at higher doping levels and evidence of coexistence between surface and bulk electronic states.

Contribution

It demonstrates the coexistence of surface and bulk states and the emergence of negative magnetoresistance in sulfur-doped Bi2Se3, highlighting the role of bulk conduction.

Findings

Magnetoresistance decreases with S doping and becomes negative at 7% doping.

Shubnikov-de Haas oscillations indicate coexistence of surface and bulk states.

Negative MR attributed to bulk conduction.

Abstract

The magneto-transport properties in Sulfur doped Bi2Se3 are investigated. The magnetoresistance (MR) decreases with increase of S content and finally for 7% (i.e. y=0.21) S doping the magnetoresistance becomes negative. This negative MR is unusual as it is observed when magnetic field is applied with the perpendicular direction to the plane of the sample. The magneto-transport behavior shows the shubnikov-de hass (SdH) oscillation indicating the coexistence of both surface and bulk states. The negative MR has been attributed to the bulk conduction.