Surface chemical treatment effect on (111) PbSnTe In Topological crystalline insulator films

In present work, the effect of Pb1-xSnxTe In In (1 1 1) surface in HCl-isopropanol (HCliPA) solution led to removal of native oxides and surface enrichment by elemental tellurium of several nm thickness. Subsequent anneals in vacuum led to desorption of elemental tellurium and revealing (1x1) surface structure. We present angle resolved photoemission spectroscopy (ARPES) measurements of the surface states on chemically prepared (1 1 1) oriented MBE-grown films of Pb1-xSnxTe, a three-dimensional topological crystalline insulator (TCI). The surface states with Dirac-like dispersion at Gamma in the surface Brillouin zone were detected. The dark current and photocurrent were found in strong dependence on the surface chemical procedure and composition. The relative simplicity of the preparation technique is encouraging, and suggests a clear path for future investigations of TCI states on alternative surface orientations in (Pb,Sn)Te solid solutions and applied aspects of TCI research.

Automated summary

This study investigated the effects of surface treatment on Pb1-xSnxTe In In (1 1 1) surface in HCl-isopropanol solution, revealing the removal of native oxides and surface enrichment by elemental tellurium, as well as subsequent desorption of tellurium and restoration of (1x1) surface structure. Angle resolved photoemission spectroscopy (ARPES) measurements on MBE-grown films of Pb1-xSnxTe showed Dirac-like dispersion surface states at Gamma. Dark current and photocurrent were observed depending on surface chemical procedure and composition, pointing towards potential applications in TCI research.