Low-Energy Dynamics of the Two-DimensionalS=1/2Heisenberg Antiferromagnet on Percolating Clusters

2006/06/08 by Ling Wang, Anders W. Sandvik
Physics and Astronomy · #Advanced Condensed Matter Physics #Computer science #Physics #Physics of Superconductivity and Magnetism #Theoretical and Computational Physics #cond-mat.str-el

paper · pdf · doi:10.1103/physrevlett.97.117204

published as Phys. Rev. Lett. 97, 117204 (2006) · 4 pages,4 figures

arxiv created 2006/06/08 · openalex publication_date 2006/09/15 · arxiv updated 2011/04/26 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We investigate the quantum dynamics of site diluted S=1/2 Heisenberg antiferromagnetic clusters at the 2D percolation threshold. We use Lanczos diagonalization to calculate the lowest excitation gap Delta and, to reach larger sizes, use quantum Monte Carlo simulations to study an upper bound for Delta obtained from sum rules involving the staggered structure factor and susceptibility. Scaling the gap distribution with the cluster length L, Delta approximately L(-), we obtain a dynamic exponent z approximately 2D(f), where D(f)=91/48 is the fractal dimensionality of the percolating cluster. This is in contrast with previous expectations of z=D(f). We argue that the low-energy excitations are due to weakly coupled effective moments formed due to local imbalance in sublattice occupation.

Citations

• Ordering near the percolation threshold in models of two-dimensional interacting bosons with quenched dilution
• Strong-disorder renormalization group study ofS=12Heisenberg antiferromagnet layers and bilayers with bond randomness, site dilution, and dimer dilution
• Classical percolation transition in the diluted two-dimensionalS=12Heisenberg antiferromagnet
• Percolation Quantum Phase Transitions in Diluted Magnets
• Spin Dependence of the Critical Concentration for the Néel State of 2D Impure Heisenberg Antiferromagnets