  The rise of topological insulators in recent years has broken new ground both
in the conceptual cognition of condensed matter physics and the promising
revolution of the electronic devices. It also stimulates the explorations of
more topological states of matter. Topological crystalline insulator is a new
topological phase, which combines the electronic topology and crystal symmetry
together. In this article, we review the recent progress in the studies of
SnTe-class topological crystalline insulator materials. Starting from the
topological identifications in the aspects of the bulk topology, surface states
calculations and experimental observations, we present the electronic
properties of topological crystalline insulators under various perturbations,
including native defect, chemical doping, strain, and thickness-dependent
confinement effects, and then discuss their unique quantum transport
properties, such as valley-selective filtering and helicity-resolved
functionalities for Dirac fermions. The rich properties and high tunability
make SnTe-class materials promising candidates for novel quantum devices.
