Tuning of carrier type, enhancement of Linear magnetoresistance and inducing ferromagnetism at room temperature with Cu doping in Bi2Te3 Topological Insulators

Abstract

Structural, resistivity, thermoelectric power, magneto-transport and magnetic properties of Cu doped Bi2Te3 topological insulators have been investigated. The tuning of charge carriers from n 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 increases with doping of Cu. Moreover, linear magnetoresistance (LMR) is observed at high magnetic field in pure Bi2Te3 which is associated to the gapless topological surface states protected by time reversal symmetry (TRS). Furthermore, doping of non-magnetic Cu induces ferromagnetism at room temperature and also enhances the magnetoresistance.