Electron-Phonon Interactions of Si100 and Ge100 Superconductors with Ba Atoms Inside
Jun Tang, Jingtao Xu, Satoshi Heguri, Hiroshi Fukuoka, Syoji Yamanaka, Koji Akai, Katsumi Tanigaki
DOI 10.1103/PhysRevLett.105.176402 · Physical Review Letters
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Abstract
The absolute density of states of isostructural Ba24Si100 and Ba24Ge100 near the Fermi level, which is very relevant for discussion on phonon-mediated superconductivity, is quantitatively evaluated to be 0.28 states eV−1/Ge atom and 0.18 states eV−1/Si atom by combining soft x-ray photoelectron spectroscopy and magnetic susceptibility measurements. The energetics of the anharmonic motions of the endohedral Ba atoms are also discussed on the basis of the 4d-core-level spectra. The discussion based on these important physical parameters concludes that the unique electron-phonon interactions do not occur due to the local Jahn-Teller distortion of the fragile open cage structure in the phonon-mediated BCS formalism. Compounds with a rigid cage would be essential to give rise to anticipated unique interactions as a key ingredient favored for superconducting paring.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| Ba24Ge100 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 0.27 | Pressure not reported | unknown |
| Ba24Ge100 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 0.24 | Pressure not reported | unknown |
| Ba24Ge100 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 3.8 | 2.8 GPa | unknown |
| Ba24Si100 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 1.4 | Pressure not reported | unknown |
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