Self-trapping and skin solitons in two-dimensional non-Hermitian lattices

Abstract: In the context of non-Hermitian photonics, we systematically investigate the spectral and dynamical aspects of two-dimensional nonlinear Hatano-Nelson lattices. In particular, we examine the interplay between self-trapping, due to nonlinearity, and propagation due to the non-Hermitian skin effect. These antagonistic effects give rise to amplitude thresholds - above which self-trapping in a single-channel dominates - that depend highly on the position of initial excitation and the degree of coupling asymmetry. Additionally, we identify two-dimensional skin soliton solutions and characterize their power thresholds and spatial profiles.