Phase separation and flux phases in the t−J model

Thomas Maurice Rice

Elisa Ercolessi, P. Pieri, M. Roncaglia

We study the so-called nonmagnetic phases (dimer and flux states) in the t-J model below half filling. We present a new phase diagram, at zero and finite temperature, that includes broad areas of phase coexistence (dimer-flux or flux-uniform), in accordance with experimental and numerical data on the possibility of separation into hole-rich and hole-poor regions. We also briefly comment on some techniques used in the literature to discuss phase separation in the t-J model.

M. Grilli, Claudio Castellani, Gabriel Kotliar

We study the phase diagram of the SU(N) t-J model. The model has been investigated in the N=\ensuremath{\infty} limit, analyzing various magnetic phases with cell doubling (dimer, flux, and uniform). We find a phase separation between a fully dimerized phase at half-filling and a hole-rich uniform phase supporting the occurrence of phase separation in the t-J model between a Fermi-liquid phase and an insulating magnetic phase.

Masao Ogata, Thomas Maurice Rice

Arnaud Ralko, Frédéric Mila, Didier Poilblanc

The doped two-dimensional quantum dimer model is investigated by numerical techniques on the square and triangular lattices, with significantly different results. On the square lattice, at small enough doping, there is always a phase separation between an insulating valence-bond solid and a uniform superfluid phase, whereas on the triangular lattice, doping leads directly to a uniform superfluid in a large portion of the resonating-valence-bond (RVB) phase. Under an applied Aharonov-Bohm flux, the superfluid exhibits quantization in terms of half-flux quanta, consistent with Q=2e elementary charge quanta in transport properties.

Michael P Marder, N. Papanicolaou, G. C. Psaltakis