title: Ionic Hamiltonians for transition metal atoms: effective exchange coupling and Kondo temperature.
abstract: An ionic Hamiltonian for describing the interaction between a metal and a d-shell transition metal atom having an orbital singlet state is introduced and its properties analyzed using the Schrieffer-Wolf transformation (exchange coupling) and the poor man's scaling method (Kondo temperature). We find that the effective exchange coupling between the metal and the atom has an antiferromagnetic or a ferromagnetic interaction depending on the kind of atomic fluctuations, either [Formula: see text] or [Formula: see text], associated with the metal-atom coupling. We present a general scheme for all those processes and calculate, for the antiferromagnetic interaction, the corresponding Kondo-temperature.
authors.affiliation: Departamento de Física Teórica de la Materia Condensada and IFIMAC, Cantoblanco, Universidad Autónoma, E-28049, Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Flores
authors.forename: E C
authors.initials: EC
authors.lastname: Goldberg