Fluctuations and $T_c$ reduction in cuprate superconductors

J. L. Tallon; J. G. Storey; J. W. Loram

paper

Fluctuations and $T_{c}$ reduction in cuprate superconductors

arXiv:0908.4428

Abstract

We analyse fluctuations about $T_{c}$ in the specific heat of (Y,Ca)Ba $_{2}$ Cu $_{3}$ O $_{7 - δ}$ , YBa $_{2}$ Cu $_{4}$ O $_{8}$ and Bi $_{2}$ Sr $_{2}$ CaCu $_{2}$ O $_{8 + δ}$ . The mean-field transition temperature, $T_{c}^{m f}$ , in the absence of fluctuations lies well above $T_{c}$ especially at low doping where it reaches as high as 150K. We show that phase and amplitude fluctuations set in simultaneously and $T_{c}^{m f}$ scales with the gap, $Δ_{0}$ , such that $2 Δ_{0} / k_{B} T_{c}^{m f}$ is comparable to the BCS weak-coupling value, 4.3, for d-wave superconductivity. We also show that $T_{c}^{m f}$ is unrelated to the pseudogap temperature, $T^{*}$ .

4 pages, 2 figures, submitted to PRL. A key follow up paper to this work is on the arXiv:0908.4430

Fluctuations and Tc​ reduction in cuprate superconductors

Abstract

Fluctuations and $T_{c}$ reduction in cuprate superconductors