Dual bulk-boundary correspondence in a nonreciprocal spin-orbit coupled zigzag lattice

We unveil a relevant non-Hermitian symmetry and hence a dual bulk-boundary correspondence (BBC) from a one-dimensional non-Hermitian Rice-Mele model including on-site dissipation, nonreciprocity, and spin-orbit coupling. To expose this dual BBC, we present the closed-form solutions for spin-up and spin-down edge modes and two explicit topological winding numbers, which are linked to each other to a perfect degree. We also demonstrate the topological zero modes and their strong insensitivity to disorder in the presence of spin-orbit coupling. We anticipate that this dual BBC may offer another route for manipulating spin currents and trigger the research for dual topological insulators in a single zigzag lattice.