Low temperature heat capacity of layered superconductors SrNi 2Ge2 and SrPd2Ge2

T. L. Hung, I. A. Chen, C. H. Huang, C. Y. Lin, C. W. Chen, Y. B. You, S. T. Jian, M. C. Yang, Y. Y. Hsu, J. C. Ho, Y. Y. Chen, H. C. Ku*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Low-temperature heat capacity C(T) of the weakly electron-correlated SrNi2Ge2 122-layer compound undergoes a superconducting transition with onset at 1.4 K and a bulk T c =0.75 K, where heat-capacity jump ratio ΔC(T c )/γT c =0.88-1.05. A small average superconducting energy gap E g (ave)=2.21 kT c =0.14 meV is derived for this multi-gap superconductor. Similar results for isostructural SrPd2Ge2 include T c (onset)=3.5 K, bulk T c of 2.92 K, ΔC(T c )/γT c =0.70 and E g (ave)=2.54 kT c =0.64 meV. The higher T c onset could be associated with stoichiometric 1:2:2 grains in the polycrystalline samples. In addition, deviations of E g /kT c from the BCS ratio of 3.5 suggest that, just like their iron-based counterpart, these 122-layer germanides may also exhibit an unconventional, fully-opened multi-gap s-wave superconductivity.

Original languageEnglish
Pages (from-to)148-155
Number of pages8
JournalJournal of Low Temperature Physics
Volume171
Issue number1-2
DOIs
Publication statusPublished - 2013 Apr

Keywords

  • 122-layer germanide
  • Heat capacity
  • Superconducting materials

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Condensed Matter Physics

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