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

doi:10.1007/s10909-012-0832-z

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

Department of Physics

Research output: Contribution to journal › Article › peer-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 language	English
Pages (from-to)	148-155
Number of pages	8
Journal	Journal of Low Temperature Physics
Volume	171
Issue number	1-2
DOIs	https://doi.org/10.1007/s10909-012-0832-z
Publication status	Published - 2013 Apr

Keywords

122-layer germanide
Heat capacity
Superconducting materials

ASJC Scopus subject areas

Atomic and Molecular Physics, and Optics
Materials Science(all)
Condensed Matter Physics

Access to Document

10.1007/s10909-012-0832-z

Cite this

@article{d73617ba0d0541f2abe3f2dce9018001,

title = "Low temperature heat capacity of layered superconductors SrNi 2Ge2 and SrPd2Ge2",

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.",

keywords = "122-layer germanide, Heat capacity, Superconducting materials",

author = "Hung, {T. L.} and Chen, {I. A.} and Huang, {C. H.} and Lin, {C. Y.} and Chen, {C. W.} and You, {Y. B.} and Jian, {S. T.} and Yang, {M. C.} and Hsu, {Y. Y.} and Ho, {J. C.} and Chen, {Y. Y.} and Ku, {H. C.}",

year = "2013",

month = apr,

doi = "10.1007/s10909-012-0832-z",

language = "English",

volume = "171",

pages = "148--155",

journal = "Journal of Low Temperature Physics",

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T1 - Low temperature heat capacity of layered superconductors SrNi 2Ge2 and SrPd2Ge2

AU - Hung, T. L.

AU - Chen, I. A.

AU - Huang, C. H.

AU - Lin, C. Y.

AU - Chen, C. W.

AU - You, Y. B.

AU - Jian, S. T.

AU - Yang, M. C.

AU - Hsu, Y. Y.

AU - Ho, J. C.

AU - Chen, Y. Y.

AU - Ku, H. C.

PY - 2013/4

Y1 - 2013/4

N2 - 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.

AB - 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.

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