The results of a tunneling study of the high-Tc, A15 superconductor V3Ga are presented. The superconducting electron-phonon interaction spectral function ±2F() is obtained for a set of samples with compositions spanning stoichiometry. These results are of particular interest since V3Ga is unusual among the high-Tc, A15 superconductors in that single-phase material can be formed on either side of stoichiometry. The results demonstrate that increased weight of ±2F() (or so-called mode softening) occurs at low energies as stoichiometry is approached either from above or below. Concomitantly log is found to show a minimum at stoichiometry. Interestingly, although Tc is a symmetric function of composition around stoichiometry, log is asymmetric. Hence, some other factor beyond mode softening is playing a significant factor in the systematics of the high Tcs exhibited by this superconductor as a function of composition.
ASJC Scopus subject areas
- Condensed Matter Physics