Green function theory for a magnetic impurity layer in a semi-infinite transverse Ising model

This paper is a theoretical investigation of the possibility that localized modes can occur in association with an impurity layer embedded within a se mi-infinite Ising ferromagnetic with a transverse field. Using a Green func tion formalism we find that, in addition to bulk spin waves, there may be l ocalized modes associated with the impurity layer and with the surface. The modes influence one another when the impurity layer is near the surface, m odifying the spin-waves' energies and the spectral intensities. (C) 2000 El sevier Science S.V. All rights reserved.