Abstract
We discuss general implications of the local spin-triplet pairing among correlated fermions that is induced by the Hund’s rule coupling in orbitally degenerate systems. The quasiparticle energies, the magnetic moment, and the superconducting gap are determined for the principal superconducting phases, in the situation with the exchange field induced by both the local Coulomb and the Hund’s rule exchange interactions. The phase diagram, as well as the evolution in an applied magnetic field of the spin-triplet paired states near the Stoner threshold, is provided for a model two-band system. The appearance of the spin-polarized superconducting phase makes the Stoner threshold a hidden critical point, since the pairing creates a small but detectable uniform magnetization. The stability of the superconducting state against the ferromagnetism with an alternant orbital ordering appearing in the strong-coupling limit is also discussed.
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Y. Maeno, H. Hashimoto, K. Yoshida, S. Nishizaki, S. Fujita, J.G. Bednorz: Nature 372, 532 (1994)
S. S. Saxena, P. Agarwal, K. Ahilan, F.M. Grosche, R.K.W. Haselwimmer, M.J. Steiner, E. Pugh, I.R. Walker, S.R. Julian, P. Monthoux, G.G. Lonzarich, A. Huxley, I. Sheikin, D. Braithwaite. J. Flouquet: Nature 406, 587 (2000) A. Huxley, I. Sheikin, E. Ressouche, N. Kernavanois, D. Braithwaite, R. Calemczuk, J. Flouquet: Phys. Rev. B 63, 144519 (2001); N. Tateiwa, T.C. Kobayashi, K. Hanazono, K. Amaya, Y. Haga, R. Settai, Y. Onuki: J. Phys.: Cond. Matter 13, L17 (2001)
C. Pfleiderer, M. Uhlarz, S.M. Hayden, R. Vollmer, H.v. Löhneysen, N.R. Bernhoeft, G.G. Lonzarich: Nature 412, 58 (2001)
D. Aoki, A. Huxley, E. Ressouche, D. Brithwaite, J. Floquet, J-P. Brison, E. Lhotel, C. Paulsen: Nature 413, 613 (2001)
A. Klejnberg, J. Spałek: J. Phys.: Cond. Matter 11, 6553 (1999)
J. Spałek: Phys. Rev. B 63, 104513 (2001)
A. Klejnberg, J. Spałek: Phys. Rev. B 61, 15542 (2000)
See e.g. E.P. Wohlfarth: J. Appl. Phys. 39, 1061 (1968). A more refined theory invokes the spin fluctuations, cf. T. Moriya: Spin Fluctuations in Itinerant-Electron Magnetism (Springer-Verlag, Berlin, 1985)
P. W. Anderson: in Frontiers and Borderlines in Many-Particle Physics, edited by R.A. Broglia and J.R. Schrieffer (North-Holland, Amsterdam, 1988) pp.1–40
The role of spin fluctuations in the pairing for a single-band case has been treated in: D. Fay and J. Appel: Phys. Rev. B 16, 2325 (1977) A. Layzer, D. Fay: Int. J. Magn. 1, 135 (1971) Solid State Commun. 15, 599 (1974). The role of the Hund’s rule in purely qualitative terms has been discussed in: G. Baskaran: Physica B 222–224, 498 (1996)
J. Spałek: Phys. Rev. B 37, 533 (1988)
A. Klejnberg, J. Spałek: unpublished
This is the so-called one-boson approach. For a brief review see J. Spałek, W. Wójcik: in Spectroscopy of Mott Insulators and Correlated Metals (Springer Series in Solid State Sciences, vol.119, Berlin, 1995) pp.41–65, and references therein
See e.g. M. Sigrist, K. Ueda: Rev. Mod. Phys. 63, 239 (1991)
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Spałek, J., Wróbel1, P., Wójcik, W. (2002). Coexistence of Spin-Triplet Superconductivity and Ferromagnetism Induced by the Hund’s Rule Exchange. In: Noce, C., Vecchione, A., Cuoco, M., Romano, A. (eds) Ruthenate and Rutheno-Cuprate Materials. Lecture Notes in Physics, vol 603. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-45814-X_5
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DOI: https://doi.org/10.1007/3-540-45814-X_5
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