Change-over of carrier type and magneto-transport property in Cu doped Bi2Te3 Topological Insulators

TL;DR

This study investigates how Cu doping in Bi2Te3 topological insulators alters carrier type, mobility, and magneto-transport properties, revealing a transition from n-type to p-type conduction and the suppression of linear magnetoresistance due to TRS breaking.

Contribution

It demonstrates the tuning of charge carriers and magneto-transport properties in Cu-doped Bi2Te3, highlighting the impact of Cu doping on topological surface states and band structure.

Findings

Carrier type switches from n to p with Cu doping.

Carrier mobility decreases as Cu doping increases.

Linear magnetoresistance is suppressed by Cu doping.

Abstract

Structural, resistivity, thermoelectric power and magneto-transport properties of Cu doped Bi2Te3 topological insulators have been investigated. The occurrence of the tuning of charge carriers from n type to p type by Cu doping at Te sites of Bi2Te3 is observed both from Hall effect and thermoelectric power measurements. Carrier mobility decreases with the doping of Cu which provides evidence of the movement of Fermi level from bulk conduction band to the bulk valence band. Thermoelectric power also increaseswith doping of Cu.Moreover linear magnetoresistance (LMR) has been observed at high magnetic field in pure Bi2Te3 which is associated to the gapless topological surface states protected by time reversal symmetry (TRS), whereas doping of Cu breaks TRS and an opening of band gap occurs which quenches the LMR.