Topological charge pumping in dimerized Kitaev chains

Abstract: We investigated the topological pumping charge of a dimerized Kitaev chain with spatially modulated chemical potential, which hosts nodal loops in parameter space and violates particle number conservation. In the simplest case, with alternatively assigned hopping and pairing terms, we show that the model can be mapped into the Rice-Mele model by a partial particle-hole transformation and subsequently supports topological charge pumping as a demonstration of the Chern number for the ground state. Beyond this special case, analytic analysis shows that the nodal loops are conic curves. Numerical simulation of a finite-size chain indicates that the pumping charge is zero for a quasiadiabatic loop within the nodal loop and is $\pm 1$ for a quasiadiabatic passage enclosing the nodal loop. Our findings unveil a hidden topology in a class of Kitaev chains.