Coherence peak and superconducting energy gap in Rb3C60 observed by muon spin relaxation

R. F. Kiefl; W. A. MacFarlane; K. H. Chow; S. Dunsiger; T. L. Duty; T. M. S. Johnston; J. W. Schneider; J. Sonier; L. Brard; R. M. Strongin; J. E. Fischer; A. B. Smith, III

doi:10.1103/PhysRevLett.70.3987

Coherence peak and superconducting energy gap in Rb3C60 observed by muon spin relaxation

R. F. Kiefl, W. A. MacFarlane, K. H. Chow, S. Dunsiger, T. L. Duty, T. M. S. Johnston, J. W. Schneider, J. Sonier, L. Brard, R. M. Strongin, J. E. Fischer, A. B. Smith, III

DOI 10.1103/PhysRevLett.70.3987 · Physical Review Letters

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Abstract

Muon spin relaxation resulting from spin exchange scattering of endohedral muonium (μ+e−) with thermal electronic excitations has been observed in the fullerene superconductor Rb3C60. The temperature dependence of T1−1 shows a coherence peak just below Tc and can be fit to the conventional Hebel-Slichter theory for spin relaxation in a superconductor with a broadened BCS density of states. The average energy gap for electronic excitations, Δ/kB=53(4) K or 2Δ/kBTc=3.6(3), is consistent with the BCS weak coupling limit.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Rb3C60 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	29.4	Pressure not reported	onset
Rb3C60 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	29	Pressure not reported	onset
K3C60 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown