Skin effect and dynamical delocalization in non-Hermitian quasicrystals with spin-orbit interaction

TL;DR

This study explores spectral and dynamical localization transitions in a non-Hermitian quasiperiodic system with Rashba spin-orbit interaction, revealing unique effects like persistent time-reversal symmetry breaking and size-dependent skin effects.

Contribution

It uncovers how Rashba spin-orbit interaction influences delocalization, skin effect, and dynamical regimes in non-Hermitian quasiperiodic systems, highlighting novel phenomena not seen without RSO.

Findings

DL transition linked with spectral changes and symmetry breaking.

Energy spectrum reality depends on system size, affecting skin effect.

Spin-orbit interaction alters skin effect directionality and induces hyper-diffusive dynamics.

Abstract

The investigations of the spectral and dynamical delocalization-localization (DL) transition have revealed intriguing features in a wide range of non-Hermitian systems. The present study aims at exploring the spectral and dynamical properties in a non-Hermitian quasiperiodic system with asymmetric hopping in the presence of Rashba Spin-Orbit (RSO) interaction. In particular, in such systems, we have identified that the DL transition is associated with a concurrent change in the energy spectrum, where the eigenstates always break the time-reversal symmetry for all strenghts of the quasiperiodic potential, contrary to the systems without RSO interaction. Remarkably, we find that the reality of energy spectrum under the open boundary condition that is frequently symbolised as a hallmark of the skin-effect, is a system-size dependent phenomena, and appears even when the associated energies are indeed complex. In addition, it is demonstrated that the spin-flip term in the RSO interaction in fact possesses a tendency to diminish the directionality of the skin-effect. On scrutinizing the dynamical attributes in our non-Hermitian system, we unveil that in spite of the fact that the spectral DL transition accords with the dynamical phase transition, interestingly, the system comes across hyper-diffusive and negative diffusion dynamical regimes depending upon the strength of the RSO interaction, in the spectrally localized regime.