Interfacial Superconductivity in the Type-III Heterostructure SnSe₂/PtTe₂

Interfacial superconductivity (IS) has been a topic of intense interest in condensed matter physics, due to its unique properties and exotic photoelectrical performance. However, there are few reports about IS systems consisting of two insulators. Here, motivated by the emergence of an insulator-metal transition in type-III heterostructures and the superconductivity in some “special” two-dimensional (2D) semiconductors via electron doping, we predict that the 2D heterostructure SnSe₂/PtTe₂ is a model system for realizing IS by using firstprinciples calculations. Our results show that due to slight but crucial interlayer charge transfer, SnSe₂/PtTe₂ turns to be a type-III heterostructure with metallic properties and shows a superconducting transition with the critical temperature (T_C) of 3.73 K. Similar to the enhanced electron-phonon coupling (EPC) in the electrondoped SnSe₂ monolayer, the IS in the SnSe₂/PtTe₂ heterostructure mainly originates from the metallized SnSe₂ layer. Furthermore, we find that its superconductivity is sensitive to tensile lattice strain, forming a domeshaped superconducting phase diagram. Remarkably, at 7% biaxial tensile strain, the superconducting T_C can increase more than twofold (8.80 K), resulting from softened acoustic phonons at the M point and enhanced EPC strength. Our study provides a concrete example for realizing IS in type-III heterostructures, which waits for future experimental verification.