Finite-Size Scaling for the Two-Dimensional Frustrated Quantum Heisenberg Antiferromagnet

Using results for the 4 × 4 and 6 × 6 lattice, we produce the first finite-size scaling analysis of the frustrated Heisenberg model in two dimensions. The results indicate a continuous phase transition from the ordered phase into an intermediate phase without long-range magnetic order, as for the (2 + 1)-dimensional nonlinear sigma-model. The intermediate phase is stable for 0.4 < J2/J1 < 0.65 and exhibits either dimerization or broken chiral symmetry. The transition to the collinear phase at J2/J1 0.65 is apparently of first order.