Topological phase transition and highly tunable topological transport in topological crystalline insulator Pb 1-x Sn x Te (111) thin films.

We report the magneotransport studies on the topological crystalline insulator (TCI) Pb1-xSnxTe (111) single crystal thin films grown by molecular beam epitaxy. By decreasing Sn content, an enhanced sheet resistance and decreased hole density are observed in Pb1-xSnxTe (111) thin films A weak antilocalization likely related to the topological surface states is observed in transport of Pb1-xSnxTe (x > 0.4) thin films, whereas a weak localization is displayed in Pb1-xSnxTe (x < 0.4) thin films This tunable weak antilocalization to weak localization transition is attributed to the open of Dirac gap because of the topological phase transition in TCI Pb1-xSnxTe. Our research has a potential application in the tunable electronic and spintronic devices and is very significant to the fundamental research based on TCI Pb1-xSnxTe thin film.