Two energy gaps in the tunneling-conductance spectra of the superconducting clathrate Ba8Si46
Yves Noat, Tristan Cren, Pierre Toulemonde, Alfonso San Miguel, François Debontridder, Vincent Dubost, Dimitri Roditchev
DOI 10.1103/PhysRevB.81.104522 · Physical Review B
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Abstract
We have studied the quasiparticle excitation spectrum of the superconductor Ba8Si46 by local tunneling spectroscopy. Using high-energy resolution achieved in superconductor-insulator-superconductor junctions we observed tunneling conductance spectra of a nonconventional shape revealing two distinct energy gaps, ΔL=1.3±0.1 meV and ΔS=0.9±0.2 meV. The analysis of tunneling data identified ΔL as the leading superconducting gap in the bulk material. A smaller and more dispersive gap ΔS is interpreted as induced either in reciprocal space, via the quasiparticle interband scattering from the leading superconducting band, or in real space, by the proximity effect to a normal layer at the surface.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| Ba8Si46 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 8.1 | Pressure not reported | unknown |
| Ba8Si46 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | — | Pressure not reported | unknown |
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