Charge density wave and superconducting phase in monolayer InSe

TL;DR

This study uses first-principles calculations to explore superconductivity and charge density waves in monolayer InSe, revealing doping-dependent phases and stability conditions at room temperature.

Contribution

It provides a detailed analysis of the interplay between superconductivity and charge density waves in monolayer InSe, including the effects of non-adiabatic corrections and doping levels.

Findings

Superconducting critical temperatures of 55-75 K at low hole doping.

Charge density wave emerges above the Lifshitz transition.

Monolayer InSe is dynamically stable at room temperature with doping.

Abstract

In this paper, the completed investigation of a possible superconducting phase in monolayer indium selenide is determined using first-principles calculations for both the hole and electron doping systems. The hole-doped dependence of the Fermi surface is exclusively fundamental for monolayer InSe. It leads to the extensive modification of the Fermi surface from six separated pockets to two pockets by increasing the hole densities. For low hole doping levels of the system, below the Lifshitz transition point, superconductive critical temperatures $T_c \sim 55-75$ K are obtained within anisotropic Eliashberg theory depending on varying amounts of the Coulomb potential from 0.2 to 0.1. However, for some hole doping above the Lifshitz transition point, the combination of the temperature dependence of the bare susceptibility and the strong electron-phonon interaction gives rise to a charge density wave that emerged at a temperature far above the corresponding $T_c$. Having included non-adiabatic effects, we could carefully analyze conditions for which either a superconductive or charge density wave phase occurs in the system. In addition, monolayer InSe becomes dynamically stable by including non-adiabatic effects for different carrier concentrations at room temperature.