Enhancement of Second-Order Non-Hermitian Skin Effect by Magnetic Fields

Chang-An Li, Björn Trauzettel, Titus Neupert, Song-Bo Zhang

Published 2022-12-30Version 1

The non-Hermitian skin effect is a unique phenomenon in which an extensive number of eigenstates are localized at the boundaries of a non-Hermitian system. Recent studies show that the non-Hermitian skin effect will be significantly suppressed by magnetic fields. In contrast, we demonstrate that the second-order skin effect (SOSE) is robust and can be enhanced by magnetic fields. Moreover, the SOSE can even be induced by magnetic fields from a trivial non-Hermitian system that does not experience any skin effect at zero fields. Such anomalous behavior is attributed to the persistence and emergence of topological line gaps in the complex energy spectrum in presence of magnetic fields. Our results describe a qualitatively new magnetic field behavior of the non-Hermitian skin effect.