体态和边缘态的电导峰

Conductance peaks of bulk states and edge states

本文对有限Su-Schriefer-Heeger(SSH)晶格的能量本征态和电导问题进行求解,着重研究了引线-样品的耦合强度对其体态和边缘态电导峰的不同影响.只有在弱耦合极限下,电导峰才显示全部体态和边缘态的能量本征值;随着耦合强度的增大,全部电导峰都逐渐偏离能量本征值并变宽变低,其中边缘态的电导峰还会逐渐消失;耦合强度继续增大,剩存的电导峰又逐渐变高变窄,并在强耦合极限下与不包含两端原子的新孤立系统的能量本征值一一对应.体态和边缘态对引线-样品耦合强度变化的不同响应可作为区分边缘态与体态的有效途径,亦可作为系统中存在边缘态的重要判据.

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.