We have investigated the specific heat of optimally doped iron chalcogenide superconductor Fe(Te0.57Se0.43) with a high-quality single crystal sample. The electronic specific heat Ce of this sample has been successfully separated from the phonon contribution using the specific heat of a nonsuperconducting sample (Fe0.90Cu0.10) (Te0.57Se0.43) as a reference. The normal-state Sommerfeld coefficient γn of the superconducting sample is found to be ~26.6 mJ/mol K2, indicating intermediate electronic correlation. The temperature dependence of Ce in the superconducting state can be best fitted using a double-gap model with 2Δs(0)/kBT c=3.92 and 2Δl(0)/kBTc=5.84. The large gap magnitudes derived from fitting, as well as the large specific heat jump of ΔCe(Tc)/γnT c~2.11, indicate strong-coupling superconductivity. Furthermore, the magnetic field dependence of specific heat shows strong evidence for multiband superconductivity.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Apr 27 2011|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics