Electron-phonon interaction and ultrasonic attenuation in the ruthenate and cuprate superconductors
Abstract
This article derives an electron-phonon interaction suitable for interpreting ultrasonic attenuation measurements in the ruthenate and cuprate superconductors. The huge anisotropy found experimentally [C. Lupien et al., Phys. Rev. Lett. 86, 5986 (2001)] in Sr2RuO4 in the normal state is accounted for in terms of the layered square-lattice structure of Sr2RuO4, and the dominant contribution to the attenuation in Sr2RuO4 is found to be due to electrons in the γ band. The experimental data in the superconducting state are found to be inconsistent with vertical line nodes in the gap in either the (100) or (110) plane. Also, a general method, based on the use of symmetry, is developed to allow for analysis of ultrasonic attenuation experiments in superconductors in which the electronic band structure is complicated or not known. Our results, both for the normal-state anisotropy and relating to the positions of the gap nodes in the superconducting state, are different from those obtained from analyses using a more traditional model for the electron-phonon interaction in terms of an isotropic electron stress tensor. Also, a brief discussion of the ultrasonic attenuation in UPt3 is given.
- Publication:
-
Physical Review B
- Pub Date:
- December 2001
- DOI:
- 10.1103/PhysRevB.65.014517
- arXiv:
- arXiv:cond-mat/0105109
- Bibcode:
- 2001PhRvB..65a4517W
- Keywords:
-
- 74.25.Ld;
- 74.20.Rp;
- Mechanical and acoustical properties elasticity and ultrasonic attenuation;
- Pairing symmetries;
- Condensed Matter - Superconductivity
- E-Print:
- 12 pages. Comments have been added to the original version of this article showing how, for the ultrasonic attenuation for a hexagonal crystal (which must be isotropic with respect to rotations about the c axis) our approach reproduces the results of the traditional isotropic electron stress tensor model