The competition of bulk and surface fields in a transverse Ising model thin film

Monte Carlo simulations have been performed to investigate the equilibrium phase behaviour of a transverse Ising model in a thin-film geometry under t he action of competing surface fields. This model is a classical isotropic vector spin model with a ferromagnetic Ising Hamiltonian and a transverse f ield applied perpendicular to the Ising z-axis. For finite values of the tr ansverse field strength, Omega, the model displays an interface localizatio n transition with a spontaneous magnetization of the film below a critical temperature T-c. However, in the limit Omega --> co, no spontaneous magneti zation of the film is observed.: In the two-phase regime, below T-c, a dege neracy exists in the magnetization profiles across the film between states of positive and negative total magnetization. The interface localization tr ansition temperature lies below the bulk critical temperature of the film f or competing surface fields.