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TT: Tiefe Temperaturen

TT 9: Neue und unkonventionelle Supraleiter

TT 9.1: Talk

Tuesday, March 25, 2003, 09:30–09:45, HSZ301

Gap Nodes and Time Reversal Symmetry Breaking in Strontium Ruthenate — •James Annett¹, Balaz Gyorffy¹, Grzegorz Litak², and Karol Wysokinski³ — ¹HH Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK — ²Department of Mechanics, Technical University of Lublin, 20-618 Lublin, Poland — ³Institute of Physics, M. Curie-Sklodowska University, 20-031 Lublin, Poland

Sr₂RuO₄is possibly the best candidate for a p-wave spin triplet superconductor. Experiments imply the pairing state is analogous to the ABM state in superfluid ³He. But such a state is in apparent contradiction to low temperature data which imply lines of gap nodes. We study the pairing state of Sr₂RuO₄ using a phenomenological model with a simple orbital dependent interaction[1]. We find that a model with two interaction parameters reproduces the experimental heat capacity and penetration depth data, and at the same time is consistent with the AMB symmetry. The gap has a horizontal line node at k₌± π/c on the β Fermi surface sheet, arising because of a strong inter-plane pairing potential. We test the sensitivity of the gap nodal structure to changes in the asumptions of the model. We show that disorder can suppress f-wave pairing components while only weakly affecting the dominant p-wave order parameter. We also compare our model with the ’interlayer-proximity effect’ model of Zhitomirsky and Rice[2].

1. J.F. Annett, B.L. Gyorffy, G. Litak and K.I. Wysokinski, Phys Rev B 66, 134514 (2002). 2. M.E. Zhitomirsky and T.M. Rice, Phys. Rev. Lett. 87, 057001 (2001).