Strong-coupling phonon-mediated scenario of superconductivity in Ca3Ir4Sn13 and Ca3(Ir0.91Co0.09)4Sn13

Jianqiang Hou; Chi Ho Wong; Rolf Lortz; Romain Sibille; Michel Kenzelmann

doi:10.1103/PhysRevB.93.134505

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Strong-coupling phonon-mediated scenario of superconductivity in Ca3Ir4Sn13 and Ca3(Ir0.91Co0.09)4Sn13

Jianqiang Hou, Chi Ho Wong, Rolf Lortz, Romain Sibille, Michel Kenzelmann

DOI 10.1103/PhysRevB.93.134505 · Physical Review B

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Abstract

We report measurements of the specific heat and electrical resistivity of Ca3(Ir0.91Co0.09)4Sn13 in comparison to Ca3Ir4Sn13. The Co substitution was chosen to suppress the structural anomaly T*=38K reported in Ca3Ir4Sn13. While the superconducting transition temperature of Ca3(Ir0.91Co0.09)4Sn13 is slightly higher than in the stoichiometric parent compound Ca3Ir4Sn13, and it displays a stronger superconducting coupling strength, the absence of a structural phase transition allows us to determine the spectral distribution of phonon states and its relation to superconductivity. The phonon density of states F(ω) and the spectral electron-phonon scattering function atr2F(ω) are determined by deconvolution of the specific heat and electrical resistivity, respectively. A dominant mode appears in both histograms at ℏω=12meV, which indicates that this phonon mode is responsible for the superconductivity in Ca3(Ir0.91Co0.09)4Sn13. The data suggest that superconductivity in this material class can be conclusively explained within a conventional strong -coupling phonon-mediated scenario.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Ca3(Ir0.91Co0.09)4Sn13 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7.5	Pressure not reported	midpoint
Ca3Ir4Sn13 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7	Pressure not reported	midpoint
Ca3(Ir0.91Co0.09)4Sn13 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7.3	Pressure not reported	midpoint
Ca3Ir4Sn13 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6.8	Pressure not reported	midpoint