Ultrasound Attenuation in Sr$_2$RuO$_4$: an Angle-Resolved Study of the Superconducting Gap Function
arXiv:cond-mat/0101319 · doi:10.1103/PhysRevLett.86.5986
Abstract
We present a study of the electronic ultrasound attenuation $α$ in the unconventional superconductor Sr$_2$RuO$_4$ . The power law behavior of $α$ at temperatures down to $T_c/30$ clearly indicates the presence of nodes in the gap. In the normal state, we find an enormous anisotropy of $α$ in the basal plane of the tetragonal structure. In the superconducting state, the temperature dependence of $α$ also exhibits significant anisotropy. We discuss these results in relation to possible gap functions.
4 pages, 3 figures. Interpretation of data clarified. Accepted for publication in PRL