Ordering kinetics in the two-dimensional classical coulomb gas of half-integer charges on a square lattice: Temperature dependent growth and roughening transition

The ordering kinetics in the Coulomb gas (CG) of half-integer charges is investigated via Monte Carlo simulations. Because of the long range Coulomb interaction, the phase ordering of this system is governed by an activation energy barrier with a logarithmic dependence on the domain size. This results in a genuine temperature-dependent growth and a roughening transition of the domain-wall morphology above T_R≃0.09±0.01. An analytical argument with numerical verification indicates that the classical CG of half-integer charges belongs to a new universality class from the viewpoint of Lai et al.’s classification of ordering kinetics [Phys. Rev. B 37, 9481 (1988)].