1972/10/01 by Philip B. Allen · 6 citations
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds
paper · doi:10.1103/physrevb.6.2577
openalex publication_date 1972/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A complete understanding of the mechanism for superconductivity requires knowledge of the details of electrons, phonons, and their interactions, and can be summarized by the function \ensuremathα2F(\ensuremathω). This function is often very similar to the phonon density of states F(\ensuremathω)=\ensuremathΣ\ensuremathδ(\ensuremathω\ensuremath-\ensuremathωQ), which can be derived from an analysis of neutron-scattering data. In this paper it is pointed out that the complete function \ensuremathα2F(\ensuremathω) is also (in principle) contained in neutron-scattering data if the intrinsic linewidth \ensuremathγQ is measured as well as the dispersion relation \ensuremathωQ. It is shown that \ensuremathα2F differs from F by having a weighting factor \frac2\ensuremathγQ\ensuremathπN(0)_\ensuremathω inside the summation, where N(0) is the electronic density of states at the Fermi surface for both spin orientations. The dimensionless coupling constant \ensuremathλ can also be expressed in terms of N(0), \ensuremathωQ, and \ensuremathγQ. In practice, for most superconductors, the average widths \ensuremathγQ are smaller than presently available resolution. However, for materials with a high density of states like \ensuremathβ\ensuremath-W superconductors, the widths \ensuremathγQ may be measurable. Also, the question of whether superconductivity arises predominantly from coupling to certain groups of phonons can be answered experimentally by searching for anomalously large widths. Estimates of average phonon widths are given for a variety of metals.