Inducing superconductivity in ultra-clean van der Waals heterojunctions of monolayer MoS₂

Inducing superconductivity in a semiconducting system with spin-orbit coupling has been an active area of research due to promising predictions and observation of exotic phases like Majorana mode. Our work has reported superconductivity in such a semiconducting system of a single-layer MoS₂ induced by orbital coupling with a superconducting system of NbSe₂. An important controlling parameter in inducing such proximity effect is the interface transparency, which in our work through low-temperature transport investigation of sharp Van-Der Waal heterojunctions of MoS₂ and NbSe₂ has been shown to be of 3 orders of magnitude higher than previously reported. Our first-principle-based study of electronic-structure calculations shows that this ultra-clean junction causes hybridization of orbitals of the two systems giving rise to states around Fermi level in MoS_2, which facilitates the appearance of proximity effect in the system having a transition temperature and superconducting gap close to that of bulk NbSe₂. Further study of the system's vortex dynamics shows a much higher pinning force compared to that of bulk, which has been primarily attributed to large defect-density in the parent MoS₂.