Superconductivity in intercalated group-IV honeycomb structures

TL;DR

This paper theoretically predicts superconductivity in intercalated group-IV honeycomb structures, estimating critical temperatures up to 20 K and revealing strongly anisotropic superconducting gaps across different compositions.

Contribution

It provides the first theoretical predictions of superconductivity in intercalated group-IV honeycomb structures and estimates their critical temperatures.

Findings

Predicted Tc of 7 K in RbGe2

Predicted Tc of 9 K in RbSi2

Predicted Tc of 11 K in SrC2

Abstract

We present a theoretical investigation on electron-phonon superconductivity of honeycomb MX$_2$ layered structures. Where X is one element of the group-IV (C, Si or Ge) and M an alkali or an alkaline-earth metal. Among the studied composition we predict a $T_c$ of 7 K in RbGe$_2$, 9 K in RbSi$_2$ and 11 K in SrC$_2$. All these compounds feature a strongly anisotropic superconducting gap. Our results show that despite the different doping and structural properties, the three families of materials fall into a similar description of its superconducting behavior. This allows us to estimate an upper critical temperature of about 20 K for the class of intercalated group-IV structures, including intercalated graphite and doped graphene.