Ordering kinetics in theq-state clock model: Scaling properties and growth laws

We present a comprehensive Monte Carlo study of the ordering kinetics in the $d=2$ ferromagnetic q-state clock model with nonconserved Glauber dynamics. In agreement with previous studies we find that q≥5 is characterized by two phase transitions occurring at temperatures Tc¹ and Tc² (Tc²<Tc¹). Phase-ordering kinetics is then investigated by rapidly quenching the system in two phases, in the quasi-long-range ordered phase (QLRO), where Tc²<T<Tc¹, and in the long-range ordered phase (LRO), where T<Tc², T being the quench temperature. Our numerical data for equal time spatial correlation function C(r,t) and structure factor $S(k,t)$ support dynamical scaling. Quench in the LRO regime is characterized by a crossover from a preasymptotic growth driven by the annealing of both vortices and interfaces to an interface driven growth at the asymptotic regime with growth exponent n0.5. In the QLRO quench regime, domains coarsen mainly via annihilation of point defects and our length-scale data for $q=9$, 12, and 20 suggests a R(t)~(t/lnt)1/2 growth law for the q-state clock model in the QLRO phase.