The two-dimensional bond-diluted quantum Heisenberg model at the classical percolation threshold

摘要

The two-dimensional antiferromagnetic S=1/2 Heisenberg model with random bonddilution is studied using quantum Monte Carlo simulation at the percolationthreshold (50% of the bonds removed). Finite-size scaling of the staggeredstructure factor averaged over the largest connected clusters of sites on L*Llattices shows that long-range order exists within the percolating fractalclusters in the thermodynamic limit. This implies that the order-disordertransition driven by bond-dilution occurs exactly at the percolation thresholdand that the exponents are classical. This result should apply also to thesite-diluted system.