台阶型类石墨烯纳米系统中的线性交流输运

Linear ac transport in step-shaped graphene system

利用紧束缚近似模型、格林函数方法和交流输运理论,研究两类台阶型石墨烯纳米系统中的电子交流输运性质。研究表明,台阶型石墨烯纳米系统中的界面散射导致直流电导变小。在费米能附近,第I类台阶型石墨烯纳米系统对外加电压作电容响应,第II类台阶型石墨烯纳米系统的半导体性质取决于窄端引线的导电性质。局域电子态密度的分布表明,狄拉克点电子局域在其中一类子晶格上无法传导,电导被抑制。当通道打开,电子态密度在两类子晶格上分布较均匀,利于电子传导。

T he properties of ac transport of step‐shaped grpahene nano‐system are investigated by employing the tight‐binding approximation ,Green's function method and ac transport theory .The results show that the dc conductances are suppressed due to the interface scattering in the step‐shaped graphene nano‐system .The step‐shaped graphene nano‐system of type I responds capacitively to the external applied voltage . While the semiconducting feature of the step‐shaped graphene nano‐system of type II is determined by the narrow connected graphene lead .According to the results of distribution of LDOS ,the conductance is suppressed due to the location of electrons only at one of the sublattices .However ,the conductance increases as the channel opens and the uniform locations of electrons on both the two sublattice .