Possible thermodynamic stability and superconductivity of antifluorite Be2BxC1−x

Jonathan E. Moussa; Jesse Noffsinger; Marvin L. Cohen

doi:10.1103/PhysRevB.78.104506

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Possible thermodynamic stability and superconductivity of antifluorite Be2BxC1−x

Jonathan E. Moussa, Jesse Noffsinger, Marvin L. Cohen

DOI 10.1103/PhysRevB.78.104506 · Physical Review B

T1

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Abstract

The Be2BxC1−x alloy in the antifluorite structure is theoretically studied as a possible superconductor. Although both Be2B and Be2C terminal phases are experimentally observed to be thermodynamically stable, our calculations suggest that the stability of the Be2B phase requires a high concentration of defects. The carbon-rich limit is expected to contain few defects and we predict the alloy to be thermodynamically accessible in the range 0≤x≤0.25. The superconducting Tc is predicted to increase with boron concentration with a value of 3–8 K at x=0.25 and a plateau of 5–13 K for x>0.4. The uncertainty in this prediction results from a small electron-phonon coupling of λ≤0.5 over the entire range of boron concentration. The material remains in the weak-coupling regime of superconductivity where Tc is sensitive to small variations in λ and μ∗.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Be2BxC1-x Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	3	Pressure not reported	unknown
MgB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	40	Pressure not reported	unknown