Abstract
Recently, neutron scattering spin-echo measurements have provided high-resolution data on the temperature dependence of the linewidth of acoustic phonons in conventional superconductors Pb and Nb [see P. Aynajian et al., Science 319, 1509 (2008)]. At low temperatures, the merging of the structure in the linewidth with a peak associated with a low-lying Kohn anomaly suggested a coincidence between and in Pb and Nb. Here we carry out a standard BCS calculation of the phonon linewidth to examine its temperature evolution and explore how close must be to unity in order to be consistent with the neutron data.
- Received 22 June 2011
DOI:https://doi.org/10.1103/PhysRevB.84.174523
©2011 American Physical Society