Europhys. Lett.
Volume 60, Number 2, October 2002
Page(s) 281 - 287
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 October 2002
DOI: 10.1209/epl/i2002-00348-5

Europhys. Lett., 60 (2) , pp. 281-287 (2002)

The penetration depth in $\chem{Sr_2RuO_4}$: Evidence for orbital-dependent superconductivity

H. Kusunose and M. Sigrist

Institut für Theoretische Physik, ETH-Hönggerberg CH-8093 Zürich, Switzerland

(Received 3 May 2002; accepted in final form 6 August 2002)

The apparent T2-temperature dependence of the London penetration depth in $\chem{Sr_2RuO_4}$ is discussed on the basis of a multi-gap model with horizontal line nodes. The influence of the nodes in combination with nonlocal electromagnetic response leads to low-temperature behaviors as $-T^2\ln T$ in the London limit and as T2 in the Pippard limit. These behaviors appear only at very low temperature. On the other hand, the interplay of the superconductivity of different bands is responsible for the observed T2-like behavior over the wide temperature range. The experimental data can be fitted well with a set of material parameters as was used in the specific-heat fitting.

74.20.Rp - Pairing symmetries (other than s-wave).
74.25.Bt - Thermodynamic properties.
74.70.Pq - Ruthenates.

© EDP Sciences 2002