Depinning phase transition in two-dimensional clock model with quenched   randomness
  With Monte Carlo simulations, we systematically investigate the depinning phase transition in the two-dimensional driven random-field clock model. Based on the short-time dynamic approach, we determine the transition field and critical exponents. The results show that the critical exponents vary with the form of the random-field distribution and the strength of the random fields, and the roughening dynamics of the domain interface belongs to the new subclass with $\zeta \neq \zeta_{loc} \neq \zeta_s$ and $\zeta_{loc} \neq 1$. More importantly, we find that the transition field and critical exponents change with the initial orientations of the magnetization of the two ordered domains. 
X. P. Qin, B. Zheng, N. J. Zhou
cond-mat.dis-nn cond-mat.stat-mech physics.comp-ph