The elastic constant CT and ultrasonic attenuation αs for (C11-C12)/2 have been measured on Sr2RuO4 with Tc* = 1.42 K. In contrast to the A1g and Eg strains, the B1g strain (εxx - εyy) strongly couples to the superconducting state, which dominantly originate from hybridized Ru-4dxy electrons on the γ Fermi surface. Taken into account impurity induced in-gap states, the T3 dependence of αs is found to be consistent with an existence of line nodes. The large reduction in CT below Tc* evidences the two-component order parameter and chiral p-wave state. Anomalous CT and αs around Ta= 1.34 K suggest a collective mode.
|Number of pages
|Physical Review B - Condensed Matter and Materials Physics
|Published - 2001