著者

Yanase Youichi Ogata Masao

出版者

一般社団法人日本物理学会

雑誌

Journal of the Physical Society of Japan (ISSN:00319015)

巻号頁・発行日

vol.72, no.3, pp.673-687, 2003-03-15

被引用文献数

10 81

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Triplet superconductivity in Sr_2RuO_4 is investigated with main interest on its internal degree of freedom. We perform a microscopic calculation to investigate how the chiral state d^^^(k) = (k_x ± ik_y)z^^^ is realized among the underlying six degenerate states. Starting from the three hand Huhhard model with spin-orbit interaction, we use a perturbation theory in order to calculate the pairing interaction. The p-wave superconductivity with T_c 〜 1.5 K is obtained in the moderately weak coupling region. It is shown that the orbital dependent superconductivity (ODS) robustly appears in Sr_2RuO_4. We determine the stabilized state by solving the Eliashberg equations. We find that the Hund coupling term as well as the spin-orbit interaction is necessary for the "symmetry breaking interaction". The main result is that the chiral state is stabilized in case of the p-wave symmetry with the main γ-band, which is obtained in the perturbation theory. When we assume the other pairing symmetry including the ƒ-wave state, the symmetry breaking interaction gives the other d-vector. The electronic structure constructed from the t_2_g-orbitals is essential for this result.