A theory of Topological Kondo Insulators

TL;DR

This paper explores how crystal field effects influence the topological properties of Kondo insulators, revealing conditions under which they can become interaction-driven topological insulators with potential surface states.

Contribution

It introduces a theoretical framework for understanding topological phases in Kondo insulators considering crystal field symmetries and analyzes their entanglement properties.

Findings

Kondo insulators can host topologically non-trivial ground states.

Entanglement spectrum analysis supports the existence of surface states.

Construction of Wannier functions for Kondo insulators is discussed.

Abstract

We examine how the properties of the Kondo insulators change when the symmetry of the underlying crystal field multiplets is taken into account. We employ the Anderson lattice model and consider its low-energy physics. We show that in a large class of crystal field configurations, Kondo insulators can develop a topological non-trivial ground-state. Such topological Kondo insulators are adiabatically connected to non-interacting insulators with unphysically large spin-orbit coupling, and as such may be regarded as interaction-driven topological insulators. We analyze the entanglement entropy of the Anderson lattice model of Kondo insulators by evaluating its entanglement spectrum. Our results for the entanglement spectrum are consistent with the surface state calculations. Lastly, we discuss the construction of the maximally localized Wannier wave functions for generic Kondo insulators.