Energy gaps and Kohn anomalies in elemental superconductors.
Science
; 319(5869): 1509-12, 2008 Mar 14.
Article
em En
| MEDLINE
| ID: mdl-18292306
ABSTRACT
The momentum and temperature dependence of the lifetimes of acoustic phonons in the elemental superconductors lead and niobium were determined by resonant spin-echo spectroscopy with neutrons. In both elements, the superconducting energy gap extracted from these measurements was found to converge with sharp anomalies originating from Fermi-surface nesting (Kohn anomalies) at low temperatures. The results indicate electron many-body correlations beyond the standard theoretical framework for conventional superconductivity. A possible mechanism is the interplay between superconductivity and spin- or charge-density-wave fluctuations, which may induce dynamical nesting of the Fermi surface.
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MEDLINE
Idioma:
En
Ano de publicação:
2008
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Article