Non-Hermitian topological devices with Chern insulators

TL;DR

This paper introduces non-Hermitian topological quantum devices based on Chern insulators that exhibit strong quantization and localization effects without magnetic fields, suitable for high-precision cryogenic sensing.

Contribution

It demonstrates a new class of simple quantum circuits with non-Hermitian topology that achieve enhanced quantization and localization, operable at liquid helium temperatures without magnetic fields.

Findings

Achieve stronger quantization than traditional Chern invariants.

Realize topological skin effect without magnetic fields or gates.

Operate effectively at liquid helium temperatures with small magnetic fields.

Abstract

Multi-terminal topological devices are a new generation of electronic devices with quantized properties robust against imperfections. In magnetic topological insulators, dissipationless edge states give functional devices in zero magnetic field, of interest for quantum metrology (resistance standard) or topological electronics (Chern networks). Here we show that a new generation of simple quantum circuits (disk, ring) with non-Hermitian topology, based on the interconnection of 1D Chern states in the quantum anomalous Hall regime, can have a much stronger quantization of their invariant than that of the Chern invariant itself, when measured in a non-metrology grade setup - that is, in industry-relevant conditions. Remarkably, the chirality-related topological skin effect is realized without the need of a magnetic field or an electrical gate, with a record degree of localization for a quantum Hall device. This new type of topological quantum devices based on magnets, with an exponential response that can be switched at small magnetic fields (about 200mT), can operate at liquid-Helium temperature with a good quantization and have some potential as cryogenic sensors for applications in high-precision impedance or magnetic field measurements.