SAMSON, J.H., 1997. Phase separation in Hubbard model. IN: Acta Physica Polonica A, 92 (2), pp. 363-366.
The Hartree-Fock ground-state phase diagram of the one-dimensional Hubbard model is calculated in the mu-U plane, restricted to phases with no charge density modulation. This allows antiferromagnetism, saturated ferromagnetism, spiral spin density waves and a collinear structure with unit cell up arrow up arrow down arrow down arrow. The spiral phase is unstable against phase separation near quarter-, half-and three-quarter-filling. For large U this occurs at hole (or electron) doping of (3t/pi(2) U)(1/3) from half-filling.
This paper was submitted for publication at the European Conference on Physics of Magnetism 96, Poznan, Poland, 24 - 28 June 1996.