Quasiparticle Interference on the Surface of Topological Crystalline Insulator Pb(1-x)Sn(x)Se

TL;DR

This study investigates the surface electronic states of the topological crystalline insulator Pb(1-x)Sn(x)Se using STM and ARPES, revealing quasiparticle interference patterns and differences in topological phases.

Contribution

It provides combined STM and ARPES analysis of surface states in Pb(1-x)Sn(x)Se, demonstrating quasiparticle interference and clarifying topological distinctions between phases.

Findings

Quasiparticle interference observed on the surface of the topological crystalline insulator.

Interference patterns explained by ARPES data and band structure models.

Pb0.77Sn0.23Se and PbSe exhibit different topological properties.

Abstract

Topological crystalline insulators represent a novel topological phase of matter in which the surface states are protected by discrete point group-symmetries of the underlying lattice. Rock-salt lead-tin-selenide alloy is one possible realization of this phase which undergoes a topological phase transition upon changing the lead content. We used scanning tunneling microscopy (STM) and angle resolved photoemission spectroscopy (ARPES) to probe the surface states on (001) Pb$_{1-x}$Sn$_{x}$Se in the topologically non-trivial (x=0.23) and topologically trivial (x=0) phases. We observed quasiparticle interference with STM on the surface of the topological crystalline insulator and demonstrated that the measured interference can be understood from ARPES studies and a simple band structure model. Furthermore, our findings support the fact that Pb$_{0.77}$Sn$_{0.23}$Se and PbSe have different topological nature.