Strain enhanced superconductivity of Mo$X_2$ ($X$=S or Se) bilayers with Na intercalation

TL;DR

This study predicts that Na intercalation and biaxial tensile strain can induce and significantly enhance superconductivity in MoX2 bilayers, with potential for practical applications due to improved phonon properties.

Contribution

It is the first to show how Na intercalation and strain can turn MoX2 bilayers into superconductors and boost their critical temperature.

Findings

Na intercalation induces superconductivity in MoX2 bilayers.

Biaxial tensile strain increases superconducting temperature up to ~10 K.

Enhanced phonon mean free path in Na-intercalated MoSe2 at room temperature.

Abstract

Mo$X_2$ ($X$=S or Se) is a semiconductor family with two-dimensional structure. And a recent calculation predicted the superconductivity in electron doped MoS$_2$ monolayer. In this work, the electronic structure and lattice dynamics of Mo$X_2$ bilayers with monolayer Na intercalated, have been calculated. According to the electron-phonon interaction, it is predicted that these bilayers can be transformed from indirect-gap semiconductors to a superconductors by Na intercalation. More interestingly, the biaxial tensile strain can significantly enhance the superconducting temperature up to $\sim10$ K in Na-intercalated MoS$_2$. In addition, the phonon mean free path at room-temperature is also greatly improved in Na intercalated MoSe$_2$, which is advantaged for related applications.