Retro-normal reflection and specular Andreev reflection in a transition metal dichalcogenides superconducting heterojunction

Abstract

Based on the Bogoliubov-de Gennes equation, the spin-resolved scattering problem through a transition metal dichalcogenides normal metal/superconductor has been investigated. It is shown that the tunneling conductances have a close relationship with the nontrivial Rashba metallic states. Without the Rashba spin–orbit interaction (RSOI), the tunneling conductances exhibit clear characteristic features for detecting the normal Rashba metal state (NRMS) and the anomalous Rashba metal state (ARMS). While in the presence of RSOI, the oscillation, hump structure, and the reentrant behavior of the tunneling conductances can be served as a smoking gun to distinguish the Rashba ring metal state (RRMS) from those nontrivial metallic states. Fundamentally, in sharp contrast to the NRMS and the ARMS where only the normal reflection and the retro-Andreev reflection can occur, the additional scattering processes of the retro-normal reflection (RNR) and the specular Andreev reflection (SAR) can take place in the present junction with the RRMS. Thus the obtained results offer a feasible way to determine the RNR, the SAR, and the nontrivial Rashba metallic states based on the transition metal dichalcogenides superconducting heterojunction.