  Recently, the topological classification of electronic states has been
extended to a new class of matter known as topological crystalline insulators.
Similar to topological insulators, topological crystalline insulators also have
spin-momentum locked surface states; but they only exist on specific crystal
planes that are protected by crystal reflection symmetry. Here, we report an
ultra-low temperature scanning tunneling microscopy and spectroscopy study on
topological crystalline insulator SnTe nanoplates grown by molecular beam
epitaxy. We observed quasiparticle interference patterns on the SnTe (001)
surface that can be interpreted in terms of electron scattering from the four
Fermi pockets of the topological crystalline insulator surface states in the
first surface Brillouin zone. A quantitative analysis of the energy dispersion
of the quasiparticle interference intensity shows two high energy features
related to the crossing point beyond the Lifshitz transition when the two
neighboring low energy surface bands near the point merge. A comparison between
the experimental and computed quasiparticle interference patterns reveals
possible spin texture of the surface states.

Mesoscale and Nanoscale Physics