Interfacial superconductivity in the type-III heterostructure SnSe₂/PtTe₂

Interfacial superconductivity (IS) has been a topic of intense interest in the 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 the type-III heterostructure and the superconductivity in some ”special” two-dimensional (2D) semiconductors via the electron doping, we predict that 2D heterostructure SnSe₂/PtTe₂ is a model system for realizing the IS by using first-principles calculations. Our results show that due to the 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 electron doped SnSe₂ monolayer, the IS in the SnSe₂/PtTe₂ heterostructure mainly originates from the metallized SnSe₂ layer. Furthermore, we find that the superconductivity is sensitive to the tensile lattice strain, forming a dome-shaped superconducting phase diagram. Remarkably, at the 7% tensile strain, the superconducting T_c can increase more than twofold (8.80 K), resulting from the softened acoustic phonon at the M point and the enhanced EPC strength. Our study provides a concrete example for realizing IS in the type-III heterostructure, which waits for future experimental verification.