Thermodynamic investigations of high-pressure superconducting state in CaLi 2 at 45 GPa

R. Szczȩśniak, D. Szczȩśniak

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Abstract

The thermodynamic properties of the high-pressure superconducting phase in CaLi 2 have been studied. A pressure value of 45 GPa has been chosen, at which the critical temperature reaches the maximum (T C = 12.9 K). The following results have been obtained. (i) The critical temperature cannot be calculated using the classical analytical formulas (McMillan or Allen-Dynes). (ii) The critical value of the Coulomb pseudopotential is high: μ * C = 0.23. Generalizing the results, the function μ * C (p) has a high value (μ * C (p) > 0. 15) in practically the entire pressure range from 28 to 60 GPa. (iii) The remaining fundamental thermodynamic parameters differ from the Bardeen, Cooper, and Schrieffer (BCS) values. In particular, the zero-temperature energy gap to the critical temperature: R 1 ≡ 2Δ (0)/k BT C = 3.95; the ratio of the specific heat for superconducting (C S) and the normal (C N) state: R 2 ≡ (C S (T C) - C N (T C)/C N (T C) = 2.01; and the parameter connected with the zero-temperature thermodynamic critical field: R 3 = T CC N (T C)/H C 2 (0) = 0.158. Finally, it has been shown that the value of the electronic effective mass is high: m */m e > 2.

Original languageEnglish
Pages (from-to)779-783
Number of pages5
JournalSolid State Communications
Volume152
Issue number9
DOIs
Publication statusPublished - May 2012
Externally publishedYes

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Keywords

  • Cali -superconductor
  • High-pressure effects
  • Thermodynamic properties

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Chemistry(all)
  • Materials Chemistry

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