Effective field approach to the Ising film in a transverse field

Within the framework of the effective field theory, we examine the phase transitions of the spin- Ising film in a transverse field. We study the critical temperature of the film as a function of the exchange interactions, the transverse field and the film thickness. We find that, if the ratio of the surface exchange interactions to the bulk ones R=Js/J is smaller than a critical value Rc, the critical temperature Tc/J of the film is smaller than the bulk critical temperature TcB/J and as R is increased further, Tc/J approaches TcB/J. On the other hand, if R>Rc, Tc/J is larger than the bulk TcB/J and the surface TcS/J critical temperatures of the corresponding semi-infinite system and as R is increased further, Tc/J approaches the surface critical temperature Tcs/J.