Orbital ordering phenomena in $d$- and $f$-electron systems

Abstract

In recent decades, novel magnetism of $d$- and $f$-electron compounds has been discussed very intensively both in experimental and theoretical research fields of condensed matter physics. It has been recognized that those material groups are in the same category of strongly correlated electron systems, while the low-energy physics of $d$- and $f$-electron compounds has been separately investigated rather in different manners. One of common features of both $d$- and $f$-electron systems is certainly the existence of active orbital degree of freedom, but in $f$-electron materials, due to the strong spin-orbit interaction in rare-earth and actinide ions, the physics seems to be quite different from that of $d$-electron systems. In general, when the number of internal degrees of freedom and relevant interactions is increased, it is possible to obtain rich phase diagram including large varieties of magnetic phases by using several kinds of theoretical techniques. However, we should not be simply satisfied with the reproduction of rich phase diagram. It is believed that more essential point is to seek for a simple principle penetrating complicated phenomena in common with $d$- and $f$-electron materials, which opens the door to a new stage in orbital physics. In this sense, it is considered to be an important task of this article to explain common features of magnetism in $d$- and $f$-electron systems from a microscopic viewpoint, using a key concept of orbital ordering, in addition to the review of the complex phase diagram of each material group.

112 pages, 38 figures

References in corpus (6)

• Magnetic transition and orbital degrees of freedom in vanadium spinels
• Orbital ordering phenomena in $d$- and $f$-electron systems
• Orbital and magnetic transitions in geometrically-frustrated vanadium spinels -- Monte Carlo study of an effective spin-orbital-lattice coupled model --
• Valence bond crystal in a pyrochlore antiferromagnet with orbital degeneracy
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Cited by in corpus (11)

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• Fermi surface instability at the hidden-order transition of URu2Si2
• Orbital ordering phenomena in $d$- and $f$-electron systems
• Pairing symmetry in a two-orbital Hubbard model on a square lattice
• Kondo Effect in an Electron System with Dynamical Jahn-Teller Impurity
• Small-scale phase separation in doped anisotropic antiferromagnets
• Fulde-Ferrell-Larkin-Ovchinnikov State in the absence of a Magnetic Field
• Microscopic Aspects of Multipole Properties of Filled Skutterudites
• Relevance of quantum fluctuations in the Anderson-Kondo model
• Ferromagnetism and orbital order in the two-orbital Hubbard model
• Deformation of SU(4) singlet spin-orbital state due to Hund's rule coupling