Superconductivity of Carbon Compounds with Sodalite Structure

TL;DR

This study explores the potential for high-temperature superconductivity in sodalite-structured carbon compounds through first-principles calculations, revealing some compounds may reach up to 100 K under high pressure.

Contribution

It provides a systematic analysis of the superconducting properties and stability of sodalite-structured carbon compounds, highlighting their potential for phonon-mediated high-$T_{c}$ superconductivity.

Findings

Some carbon sodalite compounds have $T_{c}$ up to 100 K at high pressure.

Mechanical and dynamic stability depend on pressure and doping.

Sodalite structure may be key to high-$T_{c}$ superconductivity in carbon.

Abstract

We investigate the superconductivity of carbon compounds with a sodalite structure, which are similar to hydrogen compounds showing the high-temperature superconductivity. A systematic analysis by first-principles calculations is carried out, including examination of mechanical and dynamic instabilities under external pressure $P$. These instabilities are classified on the phase diagram for the effective doping charge versus the lattice constant of the system. We also present the superconducting transition temperature $T_{\rm c}$ as a function of $P$ for many carbon compounds and a pure carbon system with the sodalite structure. Some of them have $T_{\rm c}$ of up to about 100 K at $P > \sim 30$ GPa, and the results suggest that the sodalite structure of carbon may be a key to producing phonon-mediated high-$T_{\rm c}$ superconductivity.