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Title: Quantum fluctuations and excitations in antiferromagnetic quasicrystals

Abstract

We study the effects of quantum fluctuations and the excitation spectrum for the antiferromagnetic Heisenberg model on a two-dimensional quasicrystal, by numerically solving linear spin-wave theory on finite approximants of the octagonal tiling. Previous quantum Monte Carlo results for the distribution of local staggered magnetic moments and the static spin structure factor are reproduced well within this approximate scheme. Furthermore, the magnetic excitation spectrum consists of magnonlike low-energy modes, as well as dispersionless high-energy states of multifractal nature. The dynamical spin structure factor, accessible to inelastic neutron scattering, exhibits linear-soft modes at low energies, self-similar structures with bifurcations emerging at intermediate energies, and flat bands in high-energy regions. We find that the distribution of local staggered moments stemming from the inhomogeneity of the quasiperiodic structure leads to a characteristic energy spread in the local dynamical spin susceptibility, implying distinct nuclear magnetic resonance spectra, specific for different local environments.

Authors:
 [1];  [2]
  1. Institut fuer Theoretische Physik III, Universitaet Stuttgart, D-70550 Stuttgart (Germany)
  2. Theoretische Physik, ETH Zuerich, CH-8093 Zurich (Switzerland)
Publication Date:
OSTI Identifier:
20666241
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 71; Journal Issue: 10; Other Information: DOI: 10.1103/PhysRevB.71.104427; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANTIFERROMAGNETIC MATERIALS; ANTIFERROMAGNETISM; BIFURCATION; EXCITATION; FLUCTUATIONS; HEISENBERG MODEL; INELASTIC SCATTERING; MAGNETIC MOMENTS; MONTE CARLO METHOD; NEUTRON DIFFRACTION; NMR SPECTRA; NUCLEAR MAGNETIC RESONANCE; SPIN; SPIN WAVES; STRUCTURE FACTORS

Citation Formats

Wessel, Stefan, and Milat, Igor. Quantum fluctuations and excitations in antiferromagnetic quasicrystals. United States: N. p., 2005. Web. doi:10.1103/PhysRevB.71.104427.
Wessel, Stefan, & Milat, Igor. Quantum fluctuations and excitations in antiferromagnetic quasicrystals. United States. doi:10.1103/PhysRevB.71.104427.
Wessel, Stefan, and Milat, Igor. Tue . "Quantum fluctuations and excitations in antiferromagnetic quasicrystals". United States. doi:10.1103/PhysRevB.71.104427.
@article{osti_20666241,
title = {Quantum fluctuations and excitations in antiferromagnetic quasicrystals},
author = {Wessel, Stefan and Milat, Igor},
abstractNote = {We study the effects of quantum fluctuations and the excitation spectrum for the antiferromagnetic Heisenberg model on a two-dimensional quasicrystal, by numerically solving linear spin-wave theory on finite approximants of the octagonal tiling. Previous quantum Monte Carlo results for the distribution of local staggered magnetic moments and the static spin structure factor are reproduced well within this approximate scheme. Furthermore, the magnetic excitation spectrum consists of magnonlike low-energy modes, as well as dispersionless high-energy states of multifractal nature. The dynamical spin structure factor, accessible to inelastic neutron scattering, exhibits linear-soft modes at low energies, self-similar structures with bifurcations emerging at intermediate energies, and flat bands in high-energy regions. We find that the distribution of local staggered moments stemming from the inhomogeneity of the quasiperiodic structure leads to a characteristic energy spread in the local dynamical spin susceptibility, implying distinct nuclear magnetic resonance spectra, specific for different local environments.},
doi = {10.1103/PhysRevB.71.104427},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 10,
volume = 71,
place = {United States},
year = {2005},
month = {3}
}