Conductance peaks of bulk states and edge states

Abstract

The electronic eigen-energy and the Landauer conductance of the finite Su-Schriefer-Heeger (SSH) lattice are calculated carefully, and the different effects of the lead-sample coupling strength on the conductance peaks of the bulk states and edge states are investigated. Only under the weak coupling limit, can the conductance peaks demonstrate the eigen-energy of all bulk states and edge states. With the increase of coupling strength, all the conductance peaks gradually deviate from their corresponding eigen-energy values and become wider, and the conductance peaks of the edge states will gradually disappear. In particular, after the coupling strength continues to increase to a large enough value, the conductance peaks gradually narrow again, but two of the peaks disappear, and the survival peaks will correspond to the eigen-energy of the remaining lattice system that does not contain the two atoms at both ends under the strong coupling limit. Therefore, the different responses of the conductance peaks to the varying coupling strength can be used to distinguish edge state from bulk states, and judge whether a system has any edge states.