Title

Excitations And Quantum Fluctuations In Site-Diluted Two-Dimensional Antiferromagnets

Abstract

We study the effect of site dilution and quantum fluctuations in an antiferromagnetic spin system on a square lattice within the linear spin-wave approximation. By performing numerical diagonalization in real space and finite-size scaling, we characterize the nature of the low-energy spin excitations for different dilution fractions up to the classical percolation threshold. We find nontrivial signatures of fractonlike excitations at high frequencies. Our simulations also confirm the existence of an upper bound for the amount of quantum fluctuations in the ground state of the system, leading to the persistence of long-range order up to the percolation threshold. This result is in agreement with recent neutron-scattering experimental data and quantum Monte Carlo numerical calculations. We also show that the absence of a quantum critical point below the classical percolation threshold holds for a large class of systems whose Hamiltonians can be mapped onto a system of coupled noninteracting massless bosons.

Publication Date

6-1-2004

Publication Title

Physical Review B - Condensed Matter and Materials Physics

Volume

69

Issue

21

Number of Pages

-

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1103/PhysRevB.69.214424

Socpus ID

42749107038 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/42749107038

This document is currently not available here.

Share

COinS