Superconductivity and magnetic exchange field coexistence in monolayer MoS2

Abstract

Abstract We consider spin-singlet and spin-triplet superconducting correlations with a magnetic exchange field in the electronic structure of monolayer MoS2. We investigate the coexistence effect in point of view of Andreev process. The resulting monolayer MoS2 effective Hamiltonian in the presence of an exchange field depends particularly on the spin symmetry of superconductor pairing. The effect of a magnetic exchange field on superconducting energy excitations is found to be fundamentally different for s- and p-wave symmetries. We show that the Clogston-Chandrasekhar limit for the magnitude of exchange field may be necessarily applied in the spin-singlet case, whereas there is no any limitation on the amount of applied exchange field in the presence of spin-triplet superconducting order. We investigate Andreev process in a normal/ferromagnetic superconductor (N/FS) junction on top of a monolayer MoS2. Dependence of Andreev reflection on the exchange field is explored. For normal quasiparticles incidence, no perfect Andreev reflection is achieved for spin-singlet, in contrast to the spin-triplet state. The signature of these aspects is illustrated in resulting subgap tunneling conductance, where there remains essential dynamical features of MoS2 such as topological β and electron-hole mass asymmetry α terms.