Calorimetric Evidence of Multiband Superconductivity in Ba(Fe0.925Co0.075)2As2

TL;DR

This study provides calorimetric evidence supporting multiband superconductivity with s-wave symmetry in Ba(Fe0.925Co0.075)2As2, revealing two distinct superconducting gaps consistent with theoretical predictions.

Contribution

The paper presents the first calorimetric measurement indicating two-band s-wave superconductivity in this compound, confirming theoretical models.

Findings

Evidence for two distinct superconducting gaps.

Confirmation of s+- order parameter.

Consistency with theoretical predictions.

Abstract

We report on the determination of the electronic heat capacity of a slightly overdoped (x = 0.075) Ba(Fe1-xCox)2As2 single crystal with a Tc of 21.4 K. Our analysis of the temperature dependence of the superconducting-state specific heat provides strong evidence for a two-band s-wave order parameter with gap amplitudes 2D1(0)/kBTc=1.9 and 2D2(0)/kBTc=4.4. Our result is consistent with the recently predicted s+- order parameter [I. I. Mazin et al., Phys. Rev. Lett. 101, 057003 (2008)].