Suppression of dimer correlations in the two-dimensional J(1)-J(2) Heisenberg model: An exact diagonalization study

We present an exact diagonalization study of the ground state of the spin-half J(1)-J(2) model. Dimer correlation functions and the susceptibility associated to the breaking of the translational invariance are calculated for the 4x4 and the 6x6 clusters. These results-especially when compared to the one-dimensional case, where the occurrence of a dimerized phase for large enough frustration is well established-suggest either a homogeneous spin liquid or, possibly, a dimerized state with a rather small order parameter.