Topological Dislocation Response in Elementary Semiconductors

TL;DR

This paper investigates how certain elementary semiconductors respond to crystal dislocations, revealing non-trivial electronic states localized at dislocation lines due to their topological properties.

Contribution

It introduces symmetry indicator invariants to predict dislocation responses in symmetric semiconductors and confirms these predictions with numerical simulations.

Findings

Edge dislocations exhibit non-trivial responses.

Screw dislocations always show trivial responses.

Mid-gap polarization bands are localized along dislocations in silicon, diamond, and germanium.

Abstract

We study elementary semiconductors and insulators that are symmetric under spatial inversion: silicon, diamond, germanium, and black phosphorene. These materials are ideal candidates for realizing obstructed atomic insulators, which differ from trivial atomic insulators by a quantized spatial shift of their electronic Wannier centers with respect to the atomic lattice. We use symmetry indicator invariants that allow the prediction of non-trivial responses to crystal dislocations in these materials. We find that edge dislocations generically exhibit a non-trivial response, while screw dislocations always display a trivial response. With the aid of numerical simulations of realistic tight-binding models, we confirm the presence of mid-gap polarization bands localized along dislocations in silicon, diamond, and germanium.