Superconductivity in Diamond-like BC3 Phase: A First-principles Investigation

TL;DR

This study uses first-principles calculations to explore the electronic, vibrational, and superconducting properties of BC3 phases derived from diamond, revealing superconductivity in a tetragonal metallic phase at high pressures.

Contribution

It provides the first detailed phonon and electron-phonon coupling analysis predicting superconductivity in tetragonal BC3 at high pressures.

Findings

Superconductivity with Tc around 20 K at 5 GPa

Electron-phonon coupling constant of 0.67

Decreasing Tc with increasing pressure

Abstract

Two possible phases of superhard material BC3 originating from the cubic diamond structure are investigated by ab initio pseudopotential density functional method using generalized gradient approximation (GGA). We calculate their elastic constants, electronic band structure, and density of states (DOS). Full phonon frequencies, electron-phonon coupling constant and possible superconducting Tc of the metallic phase with tetragonal symmetry (t-BC3, space group P-42m) have for the first time been investigated at 5 and 10 GPa. The calculated electron-phonon coupling (0.67) and the logarithmically-averaged frequency (862 cm-1) show superconductivity for the undoped t-BC3 with Tc = 20 K at 5 GPa, which decreases to 17.5 K at 10 GPa. Keywords: Superhard BC3, Band structure, Phonon spectra, Superconductivity PACS: 62.20.-x, 71.15.Mb, 74.10.+v, 74.20.Pq, 74.25.Kc