Specific-heat study of superconducting and normal states in FeSe1-xTex (0.6<=x<=1) single crystals: Strong-coupling superconductivity, strong electron-correlation, and inhomogeneity
| Autor: | Noji, T., Imaizumi, M., Suzuki, T., Adachi, T., Kato, M., Koike, Y. |
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| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | Journal of the Physical Society of Japan 81 (2012) 054708 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1143/JPSJ.81.054708 |
| Popis: | The electronic specific heat of as-grown and annealed single-crystals of FeSe1-xTex (0.6<=x<=1) has been investigated. It has been found that annealed single-crystals with x=0.6-0.9 exhibit bulk superconductivity with a clear specific-heat jump at the superconducting (SC) transition temperature, Tc. Both 2Delta_0/kBTc [Delta_0: the SC gap at 0 K estimated using the single-band BCS s-wave model] and Delta C/(gamma_n-gamma_0)Tc [Delta C$: the specific-heat jump at Tc, gamma_n: the electronic specific-heat coefficient in the normal state, gamma_0: the residual electronic specific-heat coefficient at 0 K in the SC state] are largest in the well-annealed single-crystal with x=0.7, i.e., 4.29 and 2.76, respectively, indicating that the superconductivity is of the strong coupling. The thermodynamic critical field has also been estimated. gamma_n has been found to be one order of magnitude larger than those estimated from the band calculations and increases with increasing x at x=0.6-0.9, which is surmised to be due to the increase in the electronic effective mass, namely, the enhancement of the electron correlation. It has been found that there remains a finite value of gamma_0 in the SC state even in the well-annealed single-crystals with x=0.8-0.9, suggesting an inhomogeneous electronic state in real space and/or momentum space. Comment: 22 pages, 1 table, 6 figures, Version 2 has been accepted for publication in J. Phys. Soc. Jpn |
| Databáze: | arXiv |
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