Observation of quantum transport in protected topological states of SnTe thin films

Synthesizing high quality thin films of topological insulators (TIs) and topological crystalline insulators (TCIs) is critical to understanding their unique properties and incorporating them in functional electronic devices. Here we report on efforts to characterize the topological states of the TCI SnTe. High quality, single-domain SnTe films are grown on SrTiO₃ by molecular beam epitaxy. Measurements of carrier density reveal conduction through both bulk and surface states in SnTe films of various thickness. In the thinnest films (6 nm), bulk conduction is largely suppressed, leaving conduction solely through surface states at the SnTe/SrTiO₃ interface. Magnetotransport measurements of the isolated surface states reveal weak antilocalization (WAL) behavior, a signature of two-dimensional topological transport. The WAL is analyzed to understand the nature of the topological transport through the surface states.