Magnetic phase diagram and transport properties of the t-J model: a spin-rotation-invariant slave-boson approach

On the basis of a spin-rotation-invariant formulation of the Kotliar-Ruckenstein slave-boson representation the t-J model is studied on a square lattice. The ground-state phase diagram is derived numerically, by taking into account also incommensurate magnetic structures. The domain of phase separation is determined. The correlation-induced band renormalization is in excellent agreement with Lanczos results. We calculated the doping dependence of Hall resistivity and thermopower using the relaxation time approximation, the results being in accord with experiments on La2-δSrδCuO4. (orig.)