Growth and electrical transport property studies of Bi2Se3 thin films with Cr or MnPc surface magnetic modification

Abstract

The Bi2Se3 family is widely regarded as the prototypical three-dimensional topological insulator, which is an ideal platform for investigating topological quantum phenomena such as the quantum anomalous Hall effect and Majorana fermions. Further application requires high-quality film growth with cost-effective and stable methods. In this work, we developed the evaporation technique to grow high-quality Bi2Se3 films and performed systematic transport studies on Bi2Se3 films with distinct magnetic surface modifications. Variable temperature-dependent resistance measurements revealed metallic conducting behavior. The magnetoresistive response was characterized by zero-field resistance minimum at low temperatures of 2 K. This behavior could be attributed to the dominance of the weak antilocalization effect. The phase coherence length at 2 K was around 300 nm. Hall measurements demonstrated that the carrier concentration of 7.45 × 1018 cm−3 at 2 K and the mobility is as high as 955 cm2/(V s), consistent with a single-carrier transport mechanism, with quantum interference dominated by topological surface states. The spin-momentum-locked nature of topological surface states endows them with magnetic sensitivity. A significant change in the quantum transport behavior was observed in Bi2Se3 thin-film samples with Cr atoms deposited on the film surface. This work demonstrated the quality of Bi2Se3 films and its potential for developing spintronic logic devices and topological electronic devices.