Phase separation in at-Jmodel
- 1 April 1990
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 41 (10), 6920-6932
- https://doi.org/10.1103/physrevb.41.6920
Abstract
We study a simple extension of the Heisenberg model that is abstracted from the large-U limit of the Hubbard Hamiltonian and includes charge fluctuations. An attempt is made to elucidate some basic features of the T=0 phase diagram within a suitable 1/N expansion. We find that the ferromagnetic boundary dictated by a naive application of the Nagaoka theorem is actually incorrect because of an instability induced by phase separation. We derive what we believe to be the correct ferromagnetic boundary for sufficiently high dimension, and provide a detailed description of the ensuing phase separation. We also find that a uniform canted antiferromagnetic state is stable over a nontrivial region of the phase diagram. Potential implications of these results for the physics of the original Hubbard model are briefly discussed.Keywords
This publication has 16 references indexed in Scilit:
- Interaction of holes within Wiegmanns approach to the Hubbard modelZeitschrift für Physik B Condensed Matter, 1989
- Unusual phases in quantum spin-1 systemsNuclear Physics B, 1988
- Two-dimensional Hubbard model with strong electron repulsionPhysical Review B, 1988
- Spin-bag mechanism of high-temperature superconductivityPhysical Review Letters, 1988
- Pseudospin approach for planar ferromagnetsNuclear Physics B, 1984
- Phase separation instability in the Hubbard modelPhysical Review B, 1974
- Single-Particle Excitations in Magnetic InsulatorsPhysical Review B, 1970
- Absence of Mott Transition in an Exact Solution of the Short-Range, One-Band Model in One DimensionPhysical Review Letters, 1968
- Single-Particle Excitations in Narrow Energy BandsPhysical Review B, 1967
- Ferromagnetism in a Narrow, Almost Half-FilledBandPhysical Review B, 1966