Abstract
Quantum transport is a stochastic process in nature. We can describe the transport proprieties of a system by all orders of cumulants of conductance. Full counting statistics (FCS) is effective to get arbitrary order of cumulant by taking derivative of cumulant generating function (CGF). Since the disorder effect caused by impurities are universal and important in nano-electronic devices, we focus on the transport proprieties in disorder system. By combing coherent potential approximation (CPA) with FCS, we can deal with cumulants using diagrammatic perturbation expansion of Green’s function. In normal-superconducting disorder system consisting normal lead and superconducting lead. The electron transport near normal-superconducting interface leads the Andreev reflection which causes the supercurrent. In this work, we developed a formalism to apply CPA-FCS method to the normal-superconducting hybrid disorder system and calculate the supercurrent under Andreev approximation and wide band limit. This is done by mapping the Green’s function into higher dimension and rewriting the expression of special terms in FCS calculation. Our theory helps us avoid solving fully perturbated Green’s function which is extremely complicated and let us better evaluate the transport proprieties in normal-superconducting hybrid disorder system.
Anyone interested is welcome to attend.