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Magnetic phases nea...
Magnetic phases near the Van Hove singularity in s- and d-band Hubbard models
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Fleck, Marcus (författare)
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Oleś, Andrzej M. (författare)
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- Hedin, Lars (författare)
- Lund University,Lunds universitet,Matematisk fysik,Fysiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Mathematical Physics,Department of Physics,Departments at LTH,Faculty of Engineering, LTH
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(creator_code:org_t)
- 1997
- 1997
- Engelska.
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Ingår i: Physical Review B. - 1550-235X. ; 56:6, s. 3159-3159
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http://dx.doi.org/10... (free)
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Abstract
Ämnesord
Stäng
- 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.
Ämnesord
- NATURVETENSKAP -- Fysik -- Den kondenserade materiens fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Condensed Matter Physics (hsv//eng)
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