Charge and spin transport across two-dimensional non-centrosymmetric semiconductor/metal interface

We theoretically study the charge conductance through a junction composed of an ordinary two-dimensional metal and a non-centrosymmetric two-dimensional semiconductor with Rashba spin–orbit coupling. A free electron approximation and scattering method are used to calculate the conductance at zero applied voltage. The impact of the Rashba coupling strength and semiconductor carrier density on the conductance was investigated. For the junctions with low barrier potential, the conductance initially decreases with increasing Rashba spin–orbit coupling strength, but reaches a minimum at a critical coupling before beginning to increase. As a function of n-doped semiconductor carrier density, the conductance exhibits a characteristic kink that occurs when the Fermi level coincides with the intersection of the Rashba-split bands. The polarization of current at zero applied voltage is also studied and found to depend strongly on interfacial scattering on the metal side but weakly on interfacial scattering on the semiconductor-side of the junction.