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Title: Role of rotational symmetry in the magnetism of a multiorbital model
Authors: Antipov, A. E.
Krivenko, I. S.
Anisimov, V. I.
Lichtenstein, A. I.
Rubtsov, A. N.
Лихтенштейн, А. И.
Issue Date: 2012
Citation: Role of rotational symmetry in the magnetism of a multiorbital model / A. E. Antipov, I. S. Krivenko, V. I. Anisimov, A. I. Lichtenstein, A. N. Rubtsov // Physical Review B - Condensed Matter and Materials Physics. — 2012. — Vol. 86. — № 15.
Abstract: Effect of rotationally invariant Hund's rule coupling on a magnetism of multiorbital Hubbard models is studied within a dynamical mean-field theory framework. Comparison of static magnetic susceptibilities and local densities of states of two- and three-orbital models of a complete rotationally invariant Coulomb interaction and a "density-density" Hartree type interaction shows the different role of spin-flip interactions for different band fillings. In the particle-hole symmetric case, the Mott-Hubbard physics dominates due to the strong effective Coulomb interaction, while for the multiple electronic configurations away from half-filling (two electrons in the three-band model) the formation of local magnetic moments due to Hund's exchange interaction becomes the most significant effect for itinerant magnetic systems. A shift of the temperature of magnetic ordering due to the rotationally invariant Hund's rule coupling is found to be the largest in a three-orbital model with a two-electron occupancy where the single particle spectrum is metallic and is not sensitive to different forms of the Coulomb vertex. A larger enhancement of the effective mass in a model with a rotationally invariant interaction is discussed. In the half-filled case we find a drastic change in the density of states close to the Mott transition which is related to the spin-flip Kondo fluctuations in a degenerate orbital case, while the corresponding shift of the magnetic transition temperature is relatively small. It is shown that a change in the ground-state degeneracy due to a different symmetry of the Coulomb interaction in the density-density model leads to a breakdown of the quasiparticle peak at the Fermi level in the proximity of a Mott transition on the metallic side. We discuss the relevance of rotationally invariant Hund's interaction in the transition metal magnetism. © 2012 American Physical Society.
SCOPUS ID: 84867194396
WOS ID: 000309385400004
PURE ID: 1074107
ISSN: 1098-0121
DOI: 10.1103/PhysRevB.86.155107
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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