rikvold 29november2007

1. Nanostructure and velocity of field-driven solid-on-solid interfacesmoving under a phonon-assisted dynamic.Phys. Rev. B76, 045422 (2007)G.M. Buendía, P.A. Rikvold, M. Kolesik, K. Park, M.A. Novotny In kinetic Monte Carlo (KMC) simulations of physical and chemical systems, the nanostructure and mobility of interfaces depend strongly on the stochastic dynamic used [1]. A physically realistic dynamic is required to obtain reliable results. This paper describes the effects of such a dynamic for a magnetic domain wall driven by an applied field and in contact with a thermal bath of lattice vibrations (phonons). The dynamic was derived from a quantum-mechanical density matrix. The surprising result, which is consistent with recent experiments [2], is that both the nanostructure and the propagation velocity of the interface are nonmonotonic functions of the applied field. These results contribute strongly to putting KMC on a sound physical foundation. [1] P.A. Rikvold and M. Kolesik, J. Phys. A 35, L117 (2002). [2] T. Meunier, et al., Phys. Rev. Lett. 98, 126601 (2007). Top: The interface structures resulting from the phonon-assisted dynamic (black and blue) at a field near zero (a) and near twice the exchange interaction J (b). The results for the commonly used Glauber dynamic are shown in red for comparison. Bottom: The propagation velocity for the phonon-assisted dynamic at temperature T = 0.6Tc (red) and 0.2Tc (black), where Tc is the critical temperature.