Interfacial superconductivity in the type-III heterostructure SnSe$_2$/PtTe$_2$

TL;DR

This study predicts interfacial superconductivity in the SnSe$_2$/PtTe$_2$ heterostructure using first-principles calculations, showing a superconducting transition at 3.73 K and tunable $T_c$ with tensile strain, providing a new platform for IS in insulator-based heterostructures.

Contribution

It introduces a novel type-III heterostructure model for interfacial superconductivity, demonstrating strain-tunable $T_c$ and the role of metallized layers via first-principles calculations.

Findings

Heterostructure exhibits superconductivity at 3.73 K.

Tensile strain enhances $T_c$ up to 8.80 K.

Superconductivity originates from metallized SnSe$_2$ layer.

Abstract

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 the some "special" two-dimensional (2D) semiconductors via the electron doping, we predict that 2D heterostructure SnSe$_2$/PtTe$_2$ 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, SnSe$_2$/PtTe$_2$ turns to be a type-III heterostructure with metallic properties and shows a superconducting transition with the critical temperature ($T_\text{c}$) of 3.73 K. Similar to the enhance electron-phonon coupling (EPC) in the electron doped SnSe$_2$ monolayer, the IS in the heterostructure SnSe$_2$/PtTe$_2$ mainly originates from the metallized SnSe$_2$ 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 $T_\text{c}$ 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 heterosturcture, which waits for future experimental verification.