The Hubbard model on the triangular lattice: A slave-boson study

We study the Hubbard model on the triangular lattice for general fillings by means of the slave-boson technique. In particular, we consider the stability regions of the paramagnetic, antiferromagnetic and linearly polarized spin-density-wave phases that are present at half-filling. The model presents a large anisotropy under I,article or hole doping of the half-filled band, a consequence of the non-bipartite nature of the lattice. We also compute the helicity modulus in the antiferromagnetic phase, which characterizes the stiffness of the magnetic order.