Signatures of edge states in the transport properties of the Su-Schrieffer-Heeger model

Abstract

We study the steady-state electronic transport in a finite Su-Schrieffer-Heeger (SSH) chain using nonequilibrium Green's function formalism. An SSH chain is coupled to metallic leads under finite bias and temperature. In the topological phase, transport at weak coupling exhibits clear edge-state signatures, including a step-like feature in the current-voltage characteristics and zero-bias conductance peak. Increasing the coupling strength dissolves these signatures due to strong hybridization between the chain and leads. On the other hand, the edge-state contributions remain robust against significant temperature changes. Furthermore, we find that edge-state transport is confined in a certain parameter window near the topological phase transition, which effectively gets narrower as we increase the length of the chain.