Toward the thorough microscopic clarification of superconducting mechanism
and gap structure in Sr2 RuO4
Takuji Nomura
Synchrotron Radiation Research Center, Japan Atomic Energy Research Institute, Mikazuki, Sayo, Hyogo
679-5148, Japan
We will discuss a mechanism of the spin-triplet p-wave superconductivity in Sr2 RuO4 from the viewpoint
of the standard Fermi liquid theory 1 . Specifically, the pairing interaction is evaluated for the realistic
electronic structure of Sr2 RuO4 , using the three-band Hubbard model and the perturbation expansion
in the Ru4d Coulomb integrals. We can indeed find an attractive momentum dependence in the spintriplet p-wave pairing channel. Thus we can regard the p-wave pairing in Sr2 RuO4 as a natural result
from the Ru4d electron correlation. Then we will concentrate on the gap structure of Sr 2 RuO4 . The
band-dependent anisotropic p-wave gap structure obtained by the microscopic theory reproduces semiquantitatively the observed temperature dependences of some key physical quantities, e.g., specific heat,
thermal conductivity and ultrasound attenuation rate 2 . Other recent theoretical developments for the
ruthenate superconductivity will also be reviewed briefly.
1
T. Nomura and K. Yamada, J. Phys. Soc. Jpn. 69 (2000) 3678; Y. Yanase, T. Jujo, T. Nomura, H.
Ikeda, T. Hotta and K. Yamada, Physics Reports 387 (2003) 1.
2
T. Nomura, cond-mat/0501231.
Sorting category: Bb Superconductivity
Keywords: Sr2 RuO4 , p-wave superconductivity
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