Work performed within the research program of the Sonderforschungsbereich 341, Köln - Aachen - Jülich
- Autor(in)
- Referenz
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10 B. S. Shastry, H. R. Krishnamurthy, P. W. Anderson, Phys. Rev. B41 (1990) 2375
11 A. G. Basile, V. Elser, Phys. Rev. B41 (1990) 4842
12 F. Gebhard, X. Zotos, Phys. Rev. B43 (1991) 1176
13 W. von der Linden, D. M. Edwards, J. Phys. Cond. Matte. 3 (1991) 4917
14 Th. Hanisch, E. Müller-Hartmann, Ann. Physi. 2 (1993) 381
15 D. C. Mattis, The Theory of Magnetism I, Springer Series in Solid State Science 17, Springer (1981)
16 P. Chandra, P. Coleman, I. Ritchey, J. Phys. I Franc. 3 (1993) 591
17 D. Vollhardt, Rev. Mod. Phys. 56 (1984) 99
18 W. F. Brinkman, T. M. Rice, Phys. Rev. B2 (1970) 4302
19 M. Fujita, M. Ishimori, K. Nakao, J. Phys. Soc. Jpn. 60 (1991) 2831
1 M. C. Gutzwiller, Phys. Rev. Lett. 10 (1963) 159
20 H. R. Krishnamurthy, C. Jayaprakash, S. Sarker, W. Wenzel, Phys. Rev. Lett. 64 (1990) 950
21 C. Jayaprakash, H. R. Krishnamurthy, S. Sarker, W. Wenzel, Europhys. Lett. 15 (1991) 625
22 M. Takahashi, J. Phys. Soc. Jpn. 51 (1982) 3475
23 S. Dahm, W. Brenig, preprint concerning the inclusion of spin flip processes into the spin density wave
24 W. Metzner, D. Vollhardt, Phys. Rev. Lett. 62 (1989) 324
25 P. Fazekas, B. Menge, E. Müller-Hartmann, Z. Phys. B - Condensed Matte. 78 (1990) 69
26 P. Richmond, G. Rickayzen, J. Phys. C2 (1969) 528
27 S. A. Trugman, Phys. Rev. B42 (1990) 6612
28 E. Müller-Hartmann, Th. Hanisch, R. Hirsch, Physic. B188 (1993) 834
29 R. Hirsch, PhD thesis, University of Cologne (1994)
2 J. Hubbard, Proc. R. Soc. Londo. A276 (1963) 238
31 P. Wurth, E. Müller-Hartmann, Ann. Phy. 4 (1995) 144
32 M. Abramowitz, I. A. Stegun, Handbook of mathematical functions, NBS, Washington (1966)
3 J. Kanamori, Prog. Theor. Phys. 30 (1963) 275
4 Y. Nagaoka, Phys. Rev. 147 (1966) 392
5 H. Tasaki, Phys. Rev. B40 (1989) 9192
6 R. Strack, D. Vollhardt, Phys. Rev. Lett. 72 (1994) 3425
7 A. Mielke, J. Phys. A24 (1991) L73;
8 H. Tasaki, Phys. Rev. Lett. 69 (1992) 1608
9 A. Mielke, H. Tasaki, Comm. Math. Phys. 158 (1993) 341
J. Phys. A24 (1991) 3311;
J. Phys. A25 (1992) 4335
- Seitenbereich
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0303 - 0328
- Schlagwort(e)
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<KWD>Hubbard model
Ferromagnetism
Kagome lattice
Triangular lattice
- Zusammenfsg.
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In order to analyse the lattice dependence of ferromagnetism in the two-dimensional Hubbard model we investigate the instability of the fully polarised ferromagnetic ground state (Nagaoka state) on the triangular, honeycomb and kagome lattices. We mainly focus on the local instability, applying single spin flip variational wave functions which include majority spin correlation effects. The question of global instability and phase separation is addressed in the framework of Hartree-Fock theory. We find a strong tendency towards Nagaoka ferromagnetism on the non-bipartite lattices (triangular, kagome) for more than half filling. For the triangular lattice we find the Nagaoka state to be unstable above a critical density of <I>n</I> = 1.887 at <I>U</I> = ∞, thereby significantly improving former variational results. For the kagome lattice the region where ferromagnetism prevails in the phase diagram widely exceeds the flat band regime. Our results even allow the stability of the Nagaoka state in a small region below half filling. In the case of the bipartite honeycomb lattice several disconnected regions are left for a possible Nagaoka ground state.
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