Effects of C, Cu, and Be substitutions in superconducting MgB2

M. J. Mehl; D. A. Papaconstantopoulos; D. J. Singh

doi:10.1103/PhysRevB.64.140509

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Effects of C, Cu, and Be substitutions in superconducting MgB2

M. J. Mehl, D. A. Papaconstantopoulos, D. J. Singh

DOI 10.1103/PhysRevB.64.140509 · Physical Review B

T1

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Abstract

Density functional calculations are used to investigate the effects of partial substitutional alloying of the B site in MgB2 with C and Be alone and combined with substitution of Mg by Cu. The effect of such substitutions on the electronic structure, electron-phonon coupling, and superconductivity are discussed. We find that Be substitution for B is unfavorable for superconductivity as it leads to a softer lattice and weaker electron-phonon couplings. Replacement of Mg by Cu increases the lattice stiffness and electron count. We estimate that with full replacement of Mg by Cu and fractional substitution of B by C, Tc values of 50 K may be attainable.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MgB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	39	Pressure not reported	unknown
MgB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	38	Pressure not reported	unknown
MgBe0.5B1.5 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	22	Pressure not reported	unknown
MgBeB Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	12	Pressure not reported	unknown
MgBe1.5B0.5 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6	Pressure not reported	unknown
MgBe2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	4	Pressure not reported	unknown
CuB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	48	Pressure not reported	unknown
CuB1.75C0.25 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	55	Pressure not reported	unknown
CuB1.5C0.5 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	53	Pressure not reported	unknown
CuB1.4C0.6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	20	Pressure not reported	unknown
CuB1.25C0.75 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	0	Pressure not reported	unknown
CuBC Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	0	Pressure not reported	unknown