Superconductivity in SrB3C3 clathrate

Abstract

We predict superconductivity for the carbon-boron clathrate SrB3C3 at 27-43 K for Coulomb pseudopotential (mu*) values between 0.17 and 0.10 using first-principles calculations with conventional electron-phonon coupling. Electrical transport measurements, facilitated by a novel in situ experimental design compatible with extreme synthesis conditions (>3000 K at 50 GPa), show non-hysteretic resistivity drops that track the calculated magnitude and pressure dependence of superconductivity for mu*=0.15, and transport measurements collected under applied magnetic fields confirm superconductivity with an onset Tc of approximately 20 K at 40 GPa. Carbon-based clathrates thus represent a new class of superconductors similar to other covalent metals like MgB2 and doped fullerenes. Carbon clathrates share structures similar to superconducting superhydrides, but covalent C-B bonds allow metastable persistence at ambient conditions.

References in corpus (8)

• Conventional superconductivity at 203 K at high pressures
• Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures
• Superconductive "sodalite"-like clathrate calcium hydride at high pressures
• The metallization and superconductivity of dense hydrogen sulfide
• High-pressure phases of silane
• Quantum Crystal Structure in the 250 K Superconducting Lanthanum Hydride
• Hydrogen "penta-graphene-like" structure stabilized by hafnium: a high-temperature conventional superconductor
• Strong electron-phonon coupling in the rare-earth carbide superconductor La2C3

Cited by in corpus (1)

• High-pressure synthesis of superhard and ultrahard materials