Spin-dynamics simulations of the triangular antiferromagnetic XY model

Kwangsik Nho, D. P. Landau

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Using Monte Carlo and spin-dynamics methods, we have investigated the dynamic behavior of the classical, antiferromagnetic XY model on a triangular lattice with linear sizes L≤300. The temporal evolutions of spin configurations were obtained by solving numerically the coupled equations of motion for each spin using fourth-order Suzuki-Trotter decompositions of exponential operators. From space- and time-displaced spin-spin correlation functions and their space-time Fourier transforms we obtained the dynamic structure factor S(q,w) for momentum q and frequency ω. Below TKT (Kosterlitz-Thouless transition), both the in-plane (Sxx) and out-of-plane (Szz) components of S(q,ω) exhibit very strong and sharp spin-wave peaks. Well above TKT, Sxx and Szz apparently display a central peak, and spin-wave signatures are still seen in Szz. In addition, we also observed an almost dispersionless domain-wall peak at high ω below Tc, (Ising transition), where long-range order appears in the staggered chirality. Above Tc, the domain-wall peak disappears for all q. The line shape of these peaks is captured reasonably well by a Lorentzian form. Using a dynamic finite-size scaling theory, we determined the dynamic critical exponent z = 1.002(3). We found that our results demonstrate the consistency of the dynamic finite-size scaling theory for the characteristic frequency ωm and the dynamic structure factor S(q,ω) itself.

Original languageEnglish
Article number174403
Pages (from-to)1744031-1744037
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume66
Issue number17
StatePublished - Nov 1 2002
Externally publishedYes

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Spin dynamics
spin dynamics
Computer simulation
Spin waves
simulation
Domain walls
magnons
domain wall
scaling
Chirality
chirality
Equations of motion
line shape
Momentum
Fourier transforms
equations of motion
signatures
exponents
Decomposition
momentum

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Spin-dynamics simulations of the triangular antiferromagnetic XY model. / Nho, Kwangsik; Landau, D. P.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 66, No. 17, 174403, 01.11.2002, p. 1744031-1744037.

Research output: Contribution to journalArticle

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