Layered Topological Crystalline Insulators

TL;DR

This paper explores layered three-dimensional topological crystalline insulators constructed from 2D TCI layers, revealing diverse topological phases characterized by mirror Chern numbers and demonstrating tunability via strain in heterostructures.

Contribution

It introduces a new approach to realize and control 3D TCI phases through stacking 2D TCI layers and analyzing mirror Chern numbers in layered materials.

Findings

Layered 3D TCI phases depend on inter-layer interactions.

New TCI phases demonstrated in PbSe/h-BN heterostructures.

Mechanical strain can tune topological properties.

Abstract

Topological crystalline insulators (TCIs) are insulating materials whose topological property relies on generic crystalline symmetries. Based on first-principles calculations, we study a three-dimensional (3D) crystal constructed by stacking two-dimensional TCI layers. Depending on the inter-layer interaction, the layered crystal can realize diverse 3D topological phases characterized by two mirror Chern numbers (MCNs) ($\mu_1,\mu_2$) defined on inequivalent mirror-invariant planes in the Brillouin zone. As an example, we demonstrate that new TCI phases can be realized in layered materials such as a PbSe (001) monolayer/h-BN heterostructure and can be tuned by mechanical strain. Our results shed light on the role of the MCNs on inequivalent mirror-symmetric planes in reciprocal space and open new possibilities for finding new topological materials.