Numerical study of flux phases in the t-J model

Martin Andersson, Stellan S. Ostlund

P. W. Leung

Masao Ogata, 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.

Didier Poilblanc, Yukio Hasegawa, Thomas Maurice Rice

Commensurate flux states for the t-J model are investigated on a finite 4\ifmmode\times\else\texttimes\fi{}4 cluster with two holes. Qualitative agreement is found with a renormalized mean-field theory; in particular, the magnetic energy exhibits an absolute minimum when the flux exactly equals the filling. Competition with the kinetic energy favors a smaller commensurate flux at intermediate J/t values. We investigate the effect of a nearest-neighbor hole-hole repulsion V. Comparing the exact ground-state results shows that the V causes an effective reduction in the value of J/t. The commensurate flux phases (CFP's) do not exhibit hole-hole attraction in real space, contrary to the t-J model for J/t\ensuremath{\ge}0.4. Therefore, the stability of the CFP's would be enhanced by a short-range repulsion between the holes.

Thomas Maurice Rice