Phase separation in the Hubbard model.

ar X iv : c on d - m at / 9 60 20 54 v 1 9 F eb 1 99 6 Phase Separation in the Hubbard Model

Making use of symmetry properties and known exact results for the Hubbard Model on bipartite lattice, we show that (1) there is no phase separation for repulsive coupling at low dopings, (2) phase separation and superconductivity co-exist in the ground states for attractive coupling in a range of filling fractions.

Se p 19 99 The magnetism of the t − t ′ Hubbard model

The magnetism of the t − t ′ Hubbard model Abstract The magnetic properties of the t − t ′ Hubbard model in the two dimensional square lattice are studied within an unrestricted Hartree Fock approximation in real space. The interplay between antiferromagnetism, ferromagnetism, phase separation and in-homogeneous magnetic textures is studied. It is shown that, at sufficiently large values of t ′...

Phase separation in the particle-hole asymmetric Hubbard model

The paramagnetic phase diagram of the Hubbard model with nearest-neighbor and next-nearest-neighbor NNN hopping on the Bethe lattice is computed at half-filling and in the weakly doped regime using the self-energy functional approach for dynamical mean-field theory. NNN hopping breaks the particle-hole symmetry and leads to a strong asymmetry of the electron-doped and hole-doped regimes. Phase ...

Phase Separation in the 2d Hubbard Model a Challenging Application of Fixed-node Qmc

Charge-spin separation in 2D Fermi systems: Singular interactions as modified commutators, and solution of the 2D Hubbard model in the bosonized approximation.

The general 2-dimensional fermion system with repulsive interactions (typified by the Hubbard Model) is bosonized, taking into account the finite on-shell forward scattering phase shift derived in earlier papers. By taking this phase shift into account in the bosonic commutation relations a consistent picture emerges showing the chargespin separation and anomalous exponents of the Luttinger liq...

Compressibility of the Two-Dimensional Infinite-U Hubbard Model

We study the interactions between the coherent quasiparticles and the incoherent Mott-Hubbard excitations and their effects on the low-energy properties in the U ` Hubbard model. Within the framework of a systematic large-N expansion, these effects first occur in the next-to-leading order in 1 N . We calculate the scattering phase shift and the free energy, and determine the quasiparticle weigh...