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Pressure dependence of the superconducting transition temperature in C$_6$Yb and C$_6$Ca

Robert P. Smith·Anna Kusmartseva·Yuen T. C. Ko·Siddharth S Saxena·Ana Akrap·Laszlo Forro·Mukul Laad·Thomas E. Weller·Mark Ellerby·Neal T. Skipper
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Abstract

We have studied the evolution, with hydrostatic pressure, of the recently discovered superconductivity in the graphite intercalation compounds C$_6$Yb and C$_6$Ca. We present pressure-temperature phase diagrams, for both superconductors, established by electrical transport and magnetization measurements. In the range 0-1.2 GPa the superconducting transition temperature increases linearly with pressure in both materials with $dT_c/dP = +0.39 K/GPa$ and $dT_c/dP = +0.50 K/GPa$ for C$_6$Yb and C$_6$Ca respectively. The transition temperature in C$_6$Yb, which has beenmeasured up to 2.3 GPa, reaches a peak at around 1.8 GPa and then starts to drop. We also discuss how this pressure dependence may be explained within a plasmon pairing mechanism.

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Robert P. Smith, Anna Kusmartseva, Yuen T. C. Ko, Siddharth S Saxena, Ana Akrap, Laszlo Forro, Mukul Laad, Thomas E. Weller, Mark Ellerby, Neal T. Skipper. 2006-04-07. Pressure dependence of the superconducting transition temperature in C$_6$Yb and C$_6$Ca. https://doi.org/10.1016/j.physb.2006.01.327

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