Green's functions theory for an interstitial magnetic impurity in a
transverse Ising ferromagnet
INTERNATIONAL JOURNAL OF MODERN PHYSICS C, (2017)DOI: 10.1142/S0129183117500498
Abstract
A Green's function formalism is used to calculate the spectrum of
localized states associated with an interstitial magnetic impurity in a
semi-infinite ferromagnet described by the transverse Ising model. The
nonresonant and resonant excitations of the system due to the impurity
(i.e. the defect modes outside and inside, respectively, the region of
the bulk and surface spin waves (SW)) are calculated numerically for the
high-temperature phase. Two situations are analyzed, depending on the
position of the interstitial impurity: the impurity is in the surface (N = 1) and the impurity is in the bulk region (N > 2).