  Magneto-transport properties of (111)-oriented single-crystal thin films of
SnTe were investigated. SnTe (111) thin films were epitaxially grown on a BaF2
substrate by molecular beam epitaxy. By optimizing the growth conditions and
the thickness of the films, the bulk carrier density could be reduced, making
it possible to detect the surface transport. In the magneto-conductance (MC)
measurement, a cusp-like feature around zero magnetic field was observed, which
is attributed to the weak-antilocalization effect of the transport in the
topological surface state. Detailed analysis of this negative MC reveals a
reduced number of transport channels contributing to the surface transport,
suggesting a strong coupling between Dirac valleys on the SnTe (111) surface,
as a characteristic feature of the transport in the multivalley structure of
TCI.
