Thickness dependence in nano-scaled transverse Ising films with bond or site dilution at surfaces

Abstract

Thickness (L) dependence for phase diagrams in nanoscaled thin films with bond and site dilutions at the surfaces, described by the transverse Ising model, are investigated by the use of the effective field theory with correlations, in order to clarify whether some characteristic phenomena found in the previous works for the most thin films (L=3) can be found by increasing the thickness in thin films. We find that the approaches to bulk values, when increasing L, are rather different between the two systems with site and bond dilutions at the surfaces, when the ratio p (p=ΩS/Ω, where ΩS and Ω are the transverse fields at the surfaces and in the inner layer) is given by p=1.0. When p=6.0, many characteristic phenomena can be obtained in the phase diagrams. Unconventional phenomena of phase diagram have also been obtained, when the value of p is changed in the thin films with a very low site or bond concentration q (q=0.1) at the surfaces.