부산대학교 도서관

Low-temperature specific heat (SH) has been measured in KxFe2-ySe2 single crystals with Tc=32 K. The SH anomaly associated with the superconducting transition is moderate and sharp, yielding a value of ΔC/T∣Tc=11.6±1.0 mJ/mol K². The residual SH coefficient γ(0) in the superconducting state at T→0 is very small with a value of about 0.39 mJ/mol K². The magnetic-field-induced enhancement of the low-T SH exhibits a rough linear feature indicating a nodeless gap. This is further supported by the scaling based on the nodeless-gap approach of the low-T data at different magnetic fields. A rough estimate indicates that the normal-state SH coefficient γn is about 6±0.5 mJ/mol K², leading to ΔC/γnT∣Tc=1.93 and placing this superconductor in the strong coupling region. [ABSTRACT FROM AUTHOR]