### 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 T_{KT} (Kosterlitz-Thouless transition), both the in-plane (S^{xx}) and out-of-plane (S^{zz}) components of S(q,ω) exhibit very strong and sharp spin-wave peaks. Well above T_{KT}, S^{xx} and S^{zz} apparently display a central peak, and spin-wave signatures are still seen in S^{zz}. In addition, we also observed an almost dispersionless domain-wall peak at high ω below T_{c}, (Ising transition), where long-range order appears in the staggered chirality. Above T_{c}, 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 ω_{m} and the dynamic structure factor S(q,ω) itself.

Original language | English |
---|---|

Article number | 174403 |

Pages (from-to) | 1744031-1744037 |

Number of pages | 7 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 66 |

Issue number | 17 |

State | Published - Nov 1 2002 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Condensed Matter Physics

### Cite this

*Physical Review B - Condensed Matter and Materials Physics*,

*66*(17), 1744031-1744037. [174403].

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

Research output: Contribution to journal › Article

*Physical Review B - Condensed Matter and Materials Physics*, vol. 66, no. 17, 174403, pp. 1744031-1744037.

}

TY - JOUR

T1 - Spin-dynamics simulations of the triangular antiferromagnetic XY model

AU - Nho, Kwangsik

AU - Landau, D. P.

PY - 2002/11/1

Y1 - 2002/11/1

N2 - 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.

AB - 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.

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M3 - Article

VL - 66

SP - 1744031

EP - 1744037

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 0163-1829

IS - 17

M1 - 174403

ER -