Nodal Gap in Fe-Based Layered Superconductor LaO_0.9F_{0.1-delta}FeAs Probed by Specific Heat Measurements

Abstract

We report the specific heat measurements on the newly discovered Fe-based layered superconductor LaO_0.9F_{0.1-delta}FeAs with the onset transition temperature T_c \approx 28 K. A nonlinear magnetic field dependence of the electronic specific heat coefficient gamma(H) has been found in the low temperature limit, which is consistent with the prediction for a nodal superconductor. The maximum gap value Delta_0 \approx 3.4$\pm$0.5 meV was derived by analyzing gamma(H) based on the d-wave model. We also detected the electronic specific heat difference between 9 T and 0 T in wide temperature region, a specific heat anomaly can be clearly observed near T_c. The Debye temperature of our sample was determined to be about 315.7 K. Our results suggest an unconventional mechanism for this new superconductor.

4 pages, 4 figures,Corrected typos

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• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Correlated electronic structure of LaOFeAs
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Cited by in corpus (10)

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• Point-Contact Spectroscopy of Iron-Based Layered Superconductor LaO${}_{0.9}$F${}_{0.1-\delta }$FeAs
• Nodal Superconductivity with Multiple Gaps in SmFeAsO${}_{0.9}$F${}_{0.1}$
• A perspective on pnictide superconductors
• Thermal properties of SmFeAs(O1-xFx) as probe of the interplay between electrons and phonons
• Pairing symmetry and properties of iron-based high temperature superconductors
• Thermodynamic properties of Ba1-xMxFe2As2 (M = La and K)
• Upper critical field, superconducting energy gaps, and Seebeck coefficient in La0.8Th0.2OFeAs
• Single vortex structure in two models of iron pnictide $s^{\pm }$ superconductivity
• Competitions of magnetism and superconductivity in FeAs-based materials