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Magnetic phases near the Van Hove singularity in s- and d-band Hubbard models

Fleck, Marcus; Oleś, Andrzej M. and Hedin, Lars LU (1997) In Physical Review B 56(6). p.3159-3159
Abstract
We investigate the magnetic instabilities of the nondegenerate (s-band) and a degenerate (d-band) Hubbard model in two dimensions using many-body effects due to particle-particle diagrams and Hund’s rule local correlations. The density of states and the position of the Van Hove singularity change depending on the value of next-nearest-neighbor hopping t′. The Stoner parameter is strongly reduced in the s-band case, and ferromagnetism survives only if the electron density is small and the band has flat regions. Due to next-nearest-neighbor hopping there are flat regions in Γ−X and Γ−Y directions. In contrast, for the d-band case the reduction of the Stoner parameter which follows from particle-particle correlations is much smaller and... (More)
We investigate the magnetic instabilities of the nondegenerate (s-band) and a degenerate (d-band) Hubbard model in two dimensions using many-body effects due to particle-particle diagrams and Hund’s rule local correlations. The density of states and the position of the Van Hove singularity change depending on the value of next-nearest-neighbor hopping t′. The Stoner parameter is strongly reduced in the s-band case, and ferromagnetism survives only if the electron density is small and the band has flat regions. Due to next-nearest-neighbor hopping there are flat regions in Γ−X and Γ−Y directions. In contrast, for the d-band case the reduction of the Stoner parameter which follows from particle-particle correlations is much smaller and ferromagnetism survives to a large extent. Inclusion of local spin-spin correlations has a limited destabilizing effect on the magnetic states. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
56
issue
6
pages
3159 - 3159
publisher
American Physical Society
external identifiers
  • Scopus:0000924433
ISSN
1550-235X
DOI
10.1103/PhysRevB.56.3159
language
English
LU publication?
yes
id
f7beac45-b240-4a58-b68e-adfff4cf37a8 (old id 8820562)
date added to LUP
2016-02-29 23:22:49
date last changed
2016-04-16 12:27:28
@misc{f7beac45-b240-4a58-b68e-adfff4cf37a8,
  abstract     = {We investigate the magnetic instabilities of the nondegenerate (s-band) and a degenerate (d-band) Hubbard model in two dimensions using many-body effects due to particle-particle diagrams and Hund’s rule local correlations. The density of states and the position of the Van Hove singularity change depending on the value of next-nearest-neighbor hopping t′. The Stoner parameter is strongly reduced in the s-band case, and ferromagnetism survives only if the electron density is small and the band has flat regions. Due to next-nearest-neighbor hopping there are flat regions in Γ−X and Γ−Y directions. In contrast, for the d-band case the reduction of the Stoner parameter which follows from particle-particle correlations is much smaller and ferromagnetism survives to a large extent. Inclusion of local spin-spin correlations has a limited destabilizing effect on the magnetic states.},
  author       = {Fleck, Marcus and Oleś, Andrzej M. and Hedin, Lars},
  issn         = {1550-235X},
  language     = {eng},
  number       = {6},
  pages        = {3159--3159},
  publisher    = {ARRAY(0x8f83858)},
  series       = {Physical Review B},
  title        = {Magnetic phases near the Van Hove singularity in s- and d-band Hubbard models},
  url          = {http://dx.doi.org/10.1103/PhysRevB.56.3159},
  volume       = {56},
  year         = {1997},
}