Subskin modes in a nonlinear non-Hermitian system

Subskin modes are distinct from conventional skin modes because they localize not at the system's edge but rather below the edge. Unlike skin modes, where a substantial number of them can accumulate at the boundaries of a system due to the non-Hermitian skin effect, subskin modes are typically limited in number to one or a few, and emerge only when the size of the system and the couplings are related in a very specific way. Nonlinear interactions can lift the restrictions on the couplings for the formation of these modes. The findings reveal the potential of subskin modes for practical applications and new research in non-Hermitian systems.