Topological non-symmorphic crystalline insulators

TL;DR

This paper introduces a new class of Z2 topological insulators protected by non-symmorphic crystalline symmetry, demonstrating their properties through a tight-binding model and extending the concept to other space groups.

Contribution

It identifies and characterizes topological non-symmorphic crystalline insulators, providing a concrete model and theoretical framework for their existence and properties.

Findings

Confirmed topological surface states in the model

Defined a Z2 topological invariant for these insulators

Extended the theory to other non-symmorphic space groups

Abstract

In this work, we identify a new class of Z2 topological insulator protected by non-symmorphic crystalline symmetry, dubbed a "topological non-symmorphic crystalline insulator". We construct a concrete tight-binding model with the non-symmorphic space group pmg and confirm the topological nature of this model by calculating topological surface states and defining a Z2 topological invariant. Based on the projective representation theory, we extend our discussion to other non-symmorphic space groups that allows to host topological non-symmorphic crystalline insulators.