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Specific heat measurements of the gap structure of the organic superconductors kappa-(ET)_2Cu[N(CN)_2]Br and kappa-(ET)_2Cu(NCS)_2

O. J. Taylor·A. Carrington·J. A. Schlueter
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Abstract

We present high resolution heat capacity measurements for the organic superconductors kappa-(ET)_2Cu[N(CN)_2]Br and kappa-(ET)_2Cu(NCS)_2 in fields up to 14 T. We use the high field data to determine the normal state specific heat and hence extract the behavior of the electronic specific heat C_{el} in the superconducting state in zero and finite fields. We find that in both materials for T/T_c<0.3, C_{el}(H=0)\sim T^2 indicating d-wave superconductivity. Our data are inconsistent with s-wave behavior, but may be fitted to a strong coupling d-wave model over the full temperature range.

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O. J. Taylor, A. Carrington, J. A. Schlueter. 2007-03-26. Specific heat measurements of the gap structure of the organic superconductors kappa-(ET)_2Cu[N(CN)_2]Br and kappa-(ET)_2Cu(NCS)_2. https://doi.org/10.1103/physrevlett.99.057001

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