English

Zero temperature ordering dynamics in two dimensional BNNNI model

Statistical Mechanics 2019-10-30 v1

Abstract

We investigate the dynamics of a two dimensional bi-axial next nearest neighbour Ising (BNNNI) model following a quench to zero temperature. The Hamiltonian is given by H=J0i,j=1L[(Si,jSi+1,j+Si,jSi,j+1)κ(Si,jSi+2,j+Si,jSi,j+2)]H = -J_0\sum_{i,j=1}^L [(S_{i,j}S_{i+1,j}+S_{i,j}S_{i,j+1}) -\kappa (S_{i,j}S_{i+2,j} + S_{i,j}S_{i,j+2})] . For κ<1\kappa <1, the system does not reach the equilibrium ground state and keep evolving in active states for ever. For κ1\kappa \geq 1, though the system reaches a final state, but it do not reach the ground state always and freezes to a striped state with a finite probability like two dimensional ferromagnetic Ising model and ANNNI model. The overall dynamical behaviour for κ>1\kappa > 1 and κ=1\kappa =1 is quite different. The residual energy decays in a power law for both κ>1 \kappa >1 and κ=1\kappa =1 from which the dynamical exponent zz have been estimated. The persistence probability shows algebraic decay for κ>1\kappa > 1 with an exponent θ=0.22±0.002\theta = 0.22 \pm 0.002 while the dynamical exponent for ordering z=2.33±0.01z=2.33\pm 0.01. For κ=1\kappa =1, the system belongs to a completely different dynamical class with θ=0.332±0.002\theta = 0.332 \pm 0.002 and z=2.47±0.04z=2.47\pm 0.04. We have computed the freezing probability for different values of κ\kappa. We have also studied the decay of autocorrelation function with time for different regime of κ\kappa values. The results have been compared with that of the two dimensional ANNNI model.

Keywords

Cite

@article{arxiv.1905.12064,
  title  = {Zero temperature ordering dynamics in two dimensional BNNNI model},
  author = {Soham Biswas and Mauricio Martin Saavedra Contreras},
  journal= {arXiv preprint arXiv:1905.12064},
  year   = {2019}
}

Comments

11 pages, 19 figures

R2 v1 2026-06-23T09:30:05.185Z