Topological insulators in filled skutterudites

TL;DR

This paper predicts new topological insulators in cerium-filled skutterudite compounds using ab initio calculations, highlighting their potential for hosting robust surface states and Majorana fermions.

Contribution

It introduces cerium-filled skutterudites as a new family of topological insulators with unique properties and potential for quantum applications.

Findings

CeOs4As12 and CeOs4Sb12 are zero-gap materials with band inversion.

These compounds become topological Kondo insulators at low temperatures.

They offer advantages for realizing Majorana fermions and novel topological phenomena.

Abstract

We propose new topological insulators in cerium filled skutterudite (FS) compounds based on ab initio calculations. We find that two compounds CeOs4As12 and CeOs4Sb12 are zero gap materials with band inversion between Os-d and Ce-f orbitals, which are thus parent compounds of two and three-dimensional topological insulators just like bulk HgTe. At low temperature, both compounds become topological Kondo insulators, which are Kondo insulators in the bulk, but have robust Dirac surface states on the boundary. This new family of topological insulators has two advantages compared to previous ones. First, they can have good proximity effect with other superconducting FS compounds to realize Majarona fermions. Second, the antiferromagnetism of CeOs4Sb12 at low temperature provides a way to realize the massive Dirac fermion with novel topological phenomena.