Mirror-time phase transition induced by non-Hermitian skin effect under magnetic field

Kai Shao, Hao Geng, Wei Chen, D. Y. Xing

Published 2021-11-08, updated 2022-02-09Version 2

The discovery of non-Hermitian skin effect (NHSE) is one of the main recent advances in non-Hermitian physics. Yet, its interplay with natural or artificial gauge fields remains elusive, which is significant for its control and applications. Here, we uncover the intriguing effects induced by the competition between the NHSE and magnetic field. We find that a magnetic field can strongly suppress and thus effectively control the NHSE. Moreover, the Onsager-Lifshitz quantization rule persists against the NHSE in the long-wavelength limit, which preserves real Landau levels. A real-to-complex transition of the entire energy spectra can be induced by the spontaneous breaking of the underlying mirror-time reversal ($\mathcal{MT}$) symmetry. We propose an order parameter to characterize the phase transition, which not only gives the phase boundary but also quantifies the $\mathcal{MT}$-symmetry breaking. Our work paves the way towards the effective control of the NHSE and the exploration of the novel $\mathcal{MT}$ phase transition in non-Hermitian magnetic systems.