Spin-polarized (001) surface states of the topological crystalline insulator Pb0.73Sn0.27Se

Abstract

We study the nature of (001) surface states in Pb0.73Sn0.27Se in the newly discovered topologicalcrystalline-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 spinresolved photoelectron spectroscopy measurements provide conclusive evidence for the formation of these (001) surface states in Pb0.73Sn0.27Se, as well as for their chiral spin structure.

Observation of topological crystalline insulator surface states on (111)-oriented Pb1−xSnxSe films

“…We have used the virtual crystal approximation for the solid solu- tion of PbSe and SnSe, both in rock-salt structure, using temperature-dependent tight binding parameters described previously 6 . We note that the band structure of rock-salt SnSe has not been verified experimentally, and hence the parameterization of this material is based solely on the results of density functional theory calculations.…”

Experimental Observation of Dirac-like Surface States and Topological Phase Transition inPb1−xSnxTe(111)Yan1, Liu2, Zang3 et al. 2014Phys. Rev. Lett.1177860View full textAdd to dashboardCite

“…The Dirac points on (111) surface are robust against translational symmetry breaking [17]. So far most of the experiments [15,16,[18][19][20][21][22][23] [24]. The experiments were performed in an ultrahigh vacuum system that consists of a MBE growth chamber, a low temperature scanning tunneling microscope (STM) (omicron) and an angle-resolved photoemission spectrometer (VG-scienta) with a base pressure better than 1×10 −10 mbar.…”

Fragility of the Dirac Cone Splitting in Topological Crystalline Insulator Heterostructures

“…9,10,12,17,21,55 After accounting for differences in composition and temperature, the dispersion of the Dirac-like states is quite consistent. Scanning tunneling microscopy observations show that these cleaved surfaces consist of atomically flat terraces separated by 50-100 nm.…”

“…54 We assume that the temperature dependence is dominated by the change of the lattice constant a 0 , and rescale our parameterization according to the Harrison rules. 55 Similarly, biaxial strain is treated by rescaling hopping parameters such that the change in energy gap with strain is in agreement with the experimentally determined deformation potential 56 and elastic constants. 57 The spectral densities projected on specific atomic layers have been calculated with the use of a tight-binding Hamiltonian for a semi-infinite system and an appropriate modification of a recursive Green's function method described by Lopez Sancho.…”