Strong electron-phonon coupling in the rare-earth carbide superconductor La2C3
SCIE
SCOPUS
- Title
- Strong electron-phonon coupling in the rare-earth carbide superconductor La2C3
- Authors
- Kim, JS; Xie, WH; Kremer, RK; Babizhetskyy, V; Jepsen, O; Simon, A; Ahn, KS; Raquet, B; Rakoto, H; Broto, JM; Ouladdiaf, B
- Date Issued
- 2007-07
- Publisher
- American Physical Soceity
- Abstract
- We present the results of a crystal structure determination using neutron powder diffraction as well as the superconducting properties of the rare-earth sesquicarbide La2C3 (T-c approximate to 13.4 K) by means of specific-heat and upper critical field measurements. From the detailed analysis of the specific heat and a comparison with ab initio electronic structure calculations, a quantitative estimate of the electron-phonon coupling strength and the logarithmic average phonon frequency is made. The electron-phonon coupling constant is determined to be lambda(ph)similar to 1.35. The electron-phonon coupling to low energy phonon modes is found to be the leading mechanism for superconductivity. Our results suggest that La2C3 is in the strong-coupling regime, and the relevant phonon modes are La related rather than C-C stretching modes. The upper critical field shows a clear enhancement with respect to the Werthamer-Helfand-Hohenberg prediction, consistent with the strong electron-phonon coupling. Possible effects on the superconducting properties due to the noncentrosymmetry of the crystal structure are discussed.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/12165
- DOI
- 10.1103/PhysRevB.76.014516
- ISSN
- 1098-0121
- Article Type
- Article
- Citation
- PHYSICAL REVIEW B, vol. 76, no. 1, 2007-07
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