Non-Hermitian topological Mott insulators in one-dimensional fermionic superlattices

Abstract

Non-Hermitian Hamiltonians have been extensively studied at the single-particle level. Here, the authors investigate interaction-induced topological Mott insulators in a non-Hermitian fermionic superlattice system, and discover an anomalous boundary effect without its Hermitian counterpart. The interplay of nonreciprocal hopping, superlattice potential, and interactions leads to the absence of edge excitations, defined via only right eigenvectors, of some in-gap states for both the neutral and charge excitation spectra, which can be restored using biorthogonal eigenvectors.