Higher-order Fabry-P\'erot Interferometer from Topological Hinge States

TL;DR

This paper introduces a novel 3D higher-order Fabry-Pérot interferometer leveraging topological hinge states, enabling unique magnetic field control and providing robust signatures for probing higher-order topological insulators.

Contribution

It proposes the first intrinsic 3D interferometer based on higher-order topology, utilizing hinge states for controllable quantum interference.

Findings

Conductance shows a beating pattern with multiple frequencies.

Interference patterns are controllable by magnetic field strength and orientation.

Provides a robust method to probe hinge states in higher-order topological insulators.

Abstract

We propose an intrinsic 3D Fabry-P\'erot type interferometer, coined "higher-order interferometer", that utilizes the chiral hinge states of second-order topological insulators and cannot be equivalently mapped to 2D space because of higher-order topology. Quantum interference patterns in the two-terminal conductance of this interferometer are controllable not only by tuning the strength but also, particularly, by rotating the direction of the magnetic field applied perpendicularly to the transport direction. Remarkably, the conductance exhibits a characteristic beating pattern with multiple frequencies with respect to field strength or direction. Our novel interferometer provides feasible and robust magneto-transport signatures to probe the particular hinge states of higher-order topological insulators.