Ordering process and Bloch wall dynamics in a two-dimensional anisotropic spin system

The ordering process of a nonconserved anisotropic XY-spin system in two-dimensional space is investigated. The dynamics is described by the motion of the domain wall, the so-called Bloch wall, which has chirality, in addition to the curvature of the interface. We obtain a convenient description for the dynamics of the domain wall, which has a generalized form of the Allen-Cahn-type equation of motion for the phase boundary, taking into account the effect of the width of the wall. We also discuss the short-scale behavior of the correlation function for this system when the system relaxes from an O(2) symmetry state to a state having O(1) symmetry.