Double-Exchange Ferromagnetism and Orbital-Fluctuation-Induced Superconductivity in Cubic Uranium Compounds
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A double-exchange mechanism for the emergence of ferromagnetism in cubic uranium compounds is proposed on the basis of a <I>j</I>–<I>j</I> coupling scheme. The idea is <I>orbital-dependent duality</I> of 5<I>f</I> electrons concerning itinerant Γ<SUB>8</SUB><SUP>−</SUP> and localized Γ<SUB>7</SUB><SUP>−</SUP> states in the cubic structure. Since orbital degree of freedom is still active in the ferromagnetic phase, orbital-related quantum critical phenomenon is expected to appear. In fact, odd-parity <I>p</I>-wave pairing compatible with ferromagnetism is found in the vicinity of an orbital ordered phase. Furthermore, even-parity <I>d</I>-wave pairing with significant odd-frequency components is obtained. A possibility to observe such exotic superconductivity in manganites is also discussed briefly.
- Journal of the Physical Society of Japan
Journal of the Physical Society of Japan 78(12), 123710-123710, 2009
THE PHYSICAL SOCIETY OF JAPAN