Theoretical Explanation of Superconductivity in C6Ca
Matteo Calandra, Francesco Mauri
DOI 10.1103/PhysRevLett.95.237002 · Physical Review Letters
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Abstract
Using density functional theory, we demonstrate that superconductivity in C6Ca is phonon mediated with λ=0.83 and phonon frequency ⟨ω⟩log=24.7 meV. The calculated isotope exponents are α(Ca)=0.24 and α(C)=0.26. Superconductivity is due mostly to C vibrations perpendicular and Ca vibrations parallel to the graphite layers. Since the electron-phonon couplings of these modes are activated by the presence of an intercalant Fermi surface, the occurrence of superconductivity in graphite intercalated compounds requires a noncomplete ionization of the intercalant.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| C6Ca Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 11 | Pressure not reported | unknown |
| C6Ca Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 11.5 | Pressure not reported | unknown |
| C6Yb Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 6.5 | Pressure not reported | unknown |
| C2Na Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 5 | Pressure not reported | unknown |
| KTI1.5C4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 2.7 | Pressure not reported | unknown |
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