Electromagnetic and thermal responses of Z topological insulators and superconductors in odd spatial dimensions

TL;DR

This paper explores how topological invariants in odd-dimensional topological insulators and superconductors manifest in electromagnetic and thermal responses, revealing new ways to detect their non-trivial topological nature.

Contribution

It clarifies the connection between bulk winding numbers and observable electromagnetic and thermal responses in chiral symmetric systems in odd dimensions.

Findings

Winding number influences electromagnetic and thermal responses.

Bulk 'chiral polarization' can detect Z non-triviality.

Magnetoelectric effects induce chiral polarization.

Abstract

The relation between bulk topological invariants and experimentally observable physical quantities is a fundamental property of topological insulators and superconductors. In the case of chiral symmetric systems in odd spatial dimensions such as time-reversal invariant topological superconductors and topological insulators with sublattice symmetry, this relation has not been well understood. We clarify that the winding number which characterizes the bulk Z non-triviality of these systems can appear in electromagnetic and thermal responses in a certain class of heterostructure systems. It is also found that the Z non-triviality can be detected in the bulk "chiral polarization", which is induced by magnetoelectric effects.