Inner skin effects on non-Hermitian topological fractals

Abstract Non-Hermitian (NH) crystals, quasicrystals, and amorphous network display an accumulation of a macroscopic number states near one its specific interfaces with vacuum, such as edge, surface, hinge, or corner. This phenomenon is known the NH skin effect, which can only be observed open boundary condition. In this regard self-similar fractals, manifesting inner boundaries in interior system, harbor novel phenomenon, effect (ISE). Then appears at fractal lattice periodic We showcase observation by implementing prominent models for insulators superconductors on representative planar Sierpinski carpet lattices. They accommodate both first-order second-order ISEs edges corners, respectively, charged well neutral Majorana fermions. Furthermore, over extended parameter regimes are tied nontrivial bulk topological invariants, yielding intrinsic ISEs. With recent success engineering phases highly tunable metamaterial platforms, photonic phononic lattices, topolectric circuits, proposed experimentally least metamaterials