Spin-polarized (001) surface states of the topological crystalline   insulator Pb_{0.73}Sn_{0.27}Se
  We study the nature of (001) surface states in Pb_{0.73}Sn_{0.27}Se in the newly discovered topological-crystalline-insulator (TCI) phase as well as the corresponding topologically trivial state above the band-gap-inversion temperature. Our calculations predict not only metallic surface states with a nontrivial chiral spin structure for the TCI case, but also nonmetallic (gapped) surface states with nonzero spin polarization when the system is a normal insulator. For both phases, angle- and spin-resolved photoelectron spectroscopy measurements provide conclusive evidence for the formation of these (001) surface states in Pb_{0.73}Sn_{0.27}Se, as well as for their chiral spin structure. 
B. M. Wojek and R. Buczko and S. Safaei and P. Dziawa and B. J.   Kowalski and M. H. Berntsen and T. Balasubramanian and M. ...
cond-mat.mtrl-sci