Superconductivity in Heavy Alkaline-Earths Intercalated Graphites

Abstract

We report the discovery of superconductivity below 1.65(6) K in Sr-intercalated graphite SrC6, by susceptibility and specific heat (Cp) measurements. In comparison with CaC6, we found that the anisotropy of the upper critical fields for SrC6 is much reduced. The Cp anomaly at Tc is smaller than the BCS prediction indicating an anisotropic superconducting gap for SrC6 similar to CaC6. The significantly lower Tc of SrC6 as compared to CaC6 can be understood in terms of "negative" pressure effects, which decreases the electron-phonon coupling for both in-plane intercalant and the out-of-plane C phonon modes. We observed no superconductivity for BaC6 down to 0.3 K.

4 pages, 4 figures, submitted to Phys. Rev. Lett

References in corpus (14)

• Superconductivity in the Intercalated Graphite Compounds C6Yb and C6Ca
• Superconductivity of bulk CaC6
• Electronic structure of superconducting graphite intercalate compounds: The role of the interlayer state
• Electronic and structural properties of superconducting MgB${}_2$, CaSi${}_2$ and related compounds
• Intercalant-Driven Superconductivity in YbC${}_6$ and CaC${}_6$
• Prediction of new crystal structure phases in metal borides: a lithium monoboride analog to MgB2
• Effect of Pressure on Superconducting Ca-intercalated Graphite CaC${}_6$
• Scanning Tunneling Spectroscopy on the novel superconductor CaC6
• Specific Heat of the Ca-Intercalated Graphite Superconductor CaC${}_6$
• Experimental evidence of s-wave superconductivity in bulk CaC${}_6$
• Possibility of superconductivity in graphite intercalated with alkaline earths investigated with density functional theory
• Electrons and phonons in the ternary alloy CaAl${}_{2-x}$Si${}_x$} as a function of composition
• Large Ca Isotope Effect in CaC6
• Combining the advantages of superconducting MgB2 and CaC6 in one material: suggestions from first-principles calculations

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