Two-carrier transport and multi-channel weak antilocalization in SnTe thin films grown by MBE

SnTe has recently been identified as a four-fold degenerate topological system where each (001) surface accommodates four identically-chiral Dirac surface states [1]. The surface states were successfully studied by ARPES and STM [2,3]. We perform magnetotransport measurements at 2K and up to 5T on epitaxial SnTe thin films grown by MBE on BaF$_{\mathrm{2}}$ (001). We report the observation of a two-carrier contribution to the magnetotransport as well as a multi-channel weak antilocalization (WAL) correction to the low field magnetoresistance. Analysis of the WAL using the HLN model [4] yields 0.75\textless $\alpha $\textless 2.5 suggesting evidence of intervalley coupling on the surface of SnTe. Films grown under different growth conditions are discussed and compared. [1] T.H. Hsieh et al. \quad Nature Commun$.$ \textbf{3, }982 (2012). [2] S.X. Yu et al. Nature Commun$. $\textbf{3, }1192 (2012). Tanaka, Y. et al. Nature Phys$. $\textbf{8, }800 (2012). [3] Okada, Y. et al. Science 1239451 (2013). [4] Hikami et al. Prog. Theor. Phys. \textbf{63} 707 (1980). Supported by NSF-DMR-0907007, partly by NSF-DMR-1207469, ONR-N00014-13-1-0301, and MIT MRSEC through NSF-DMR-0819762 and partly by DOE under Contract DE-AC02-06CH11357.