University
of Toronto
Physics Department
Quantum Optics and Condensed Matter
MONDAY SEMINAR
University
of Toronto
| Speaker : | Dr. Andrew MacFarlane
University of Toronto Department of Physics |
| Topic : | ULTRASOUND AND THE SYMMETRY OF THE SUPERCONDUCTING ORDER PARAMETER IN Sr2RuO4 |
| Time : | Monday, January 22, 2001 at 12:10 p.m. |
| Place : | Room MP408, Burton Tower 60 St. George Street / 255 Huron Street |
Abstract
The dominant source of damping of high frequency sound waves in pure metals at low temperature is coupling to the conduction electrons. Thus, the ultrasound attenuation alpha changes significantly at a superconducting transition, dropping quickly as the energy gap opens. For an energy gap which varies with direction in the crystal, the detailed temperature variation of alpha depends on this anisotropy relative to the vectors (propagation and polarization) characterizing the sound wave. Alpha is thus one of only a few bulk angle-sensitive probes of the excitations of the superconducting state. In this talk I will give an elementary introduction to the technique and its application to conventional and unconventional superconductors. I will then present some new results on the unconventional low Tc superconductor Sr2RuO4.
Local Host: Professor
Louis Taillefer
(416-978-7868)