Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Originally published in Science Express on 21 February 2008
Science 14 March 2008:
Vol. 319. no. 5869, pp. 1509 - 1512
DOI: 10.1126/science.1154115
Prev | Table of Contents | Next

Reports

Energy Gaps and Kohn Anomalies in Elemental Superconductors

P. Aynajian,1 T. Keller,1,2 L. Boeri,1 S. M. Shapiro,3 K. Habicht,4 B. Keimer1*

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.

1 Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
2 ZWE FRM-II, Technical University of Munich, Lichtenbergstrasse 1, D-85748 Garching, Germany.
3 Brookhaven National Laboratory, Upton, NY 11973–5000, USA.
4 Hahn Meitner Institute, Glienicker Strasse 100, D-14109 Berlin, Germany.

* To whom correspondence should be addressed. E-mail: b.keimer{at}fkf.mpg.de

Read the Full Text

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)