Inversion-symmetry protected chiral hinge states in stacks of doped quantum Hall layers

TL;DR

This paper demonstrates that stacked, doped quantum Hall layers with inversion symmetry can host higher-order topological insulators featuring protected chiral hinge states, driven by an external magnetic field.

Contribution

It introduces a new class of higher-order topological insulators in layered systems with inversion symmetry, driven by magnetic fields and characterized by a non-trivial ${\mathbb Z}_2$ invariant.

Findings

Stacked doped layers can host chiral hinge states.

Magnetic field induces a higher-order topological phase.

Silicene multilayers are promising experimental platforms.

Abstract

We prove the existence of higher-order topological insulators with protected chiral hinge modes in quasi-two-dimensional systems made out of coupled layers stacked in an inversion-symmetric manner. In particular, we show that an external magnetic field drives a stack of alternating p- and n-doped buckled honeycomb layers into a higher-order topological phase, characterized by a non-trivial three-dimensional ${\mathbb Z}_2$ invariant. We identify silicene multilayers as a potential material platform for the experimental detection of this novel topological insulating phase.