Temperature Dependence of Linked Gap and Surface State Evolution in the Mixed Valent Topological Insulator SmB6

TL;DR

This paper investigates how the surface states and bulk gap of the mixed valence topological insulator SmB6 evolve with temperature, using detailed ARPES measurements to understand the interplay between temperature, gap, and surface states.

Contribution

It provides a comprehensive analysis of the temperature dependence of the bulk gap and surface states in SmB6, clarifying their origin, magnitude, and role in transport.

Findings

Temperature affects the bulk gap and surface state evolution.

The bulk gap's origin and magnitude are clarified.

Surface states persist and evolve with temperature.

Abstract

Taken together and viewed holistically, recent theory, low temperature (T) transport, photoelectron spectroscopy and quantum oscillation experiments have built a very strong case that the paradigmatic mixed valence insulator SmB6 is currently unique as a three-dimensional strongly correlated topological insulator (TI). As such, its many-body T-dependent bulk gap brings an extra richness to the physics beyond that of the weakly correlated TI materials. How will the robust, symmetry-protected TI surface states evolve as the gap closes with increasing T? For SmB6 exploiting this opportunity first requires resolution of other important gap-related issues, its origin, its magnitude, its T-dependence and its role in bulk transport. In this paper we report detailed T-dependent angle resolved photoemission spectroscopy (ARPES) measurements that answer all these questions in a unified way.