Surface reconstruction in a tight-binding model for the topological Kondo insulator SmB6

TL;DR

This paper investigates how a 2x1 surface reconstruction affects the topological surface states of the Kondo insulator SmB6, revealing potential modifications in electronic structure and quasiparticle interference signals.

Contribution

It provides a detailed analysis of the impact of surface reconstruction on SmB6's surface states, highlighting conditions for weak or strong perturbations and their experimental signatures.

Findings

Weak reconstruction causes minor band backfolding.

Strong reconstruction can alter surface dispersion and induce Lifshitz transitions.

Reconstruction can produce novel peaks in quasiparticle interference signals.

Abstract

For the strongly correlated topological insulator SmB6 we discuss the influence of a 2x1 reconstruction of the (001) surface on the topological surface states. Depending on microscopic details, the reconstruction can be a weak or a strong perturbation to the electronic states. While the former leads to a weak backfolding of surface bands only, the latter can modify the surface-state dispersion and lead to a Lifshitz transition. We analyze the quasiparticle interference signal: while this tends to be weak in models for SmB6 in the absence of surface reconstruction, we find that the 2x1 reconstruction can induce novel peaks. We discuss experimental implications.