On the ground states of some s-d exchange Kondo Hamiltonians

Abstract

Renormalisation-group calculations show that the ground state of an arbitrary mathematical Kondo Hamiltonian is not a state of zero spin in general. An S=0 state only occurs when special relations exist between the number of suitably coupled scattering channels and the magnitude of the impurity spin. A study of the physics underlying the formation of an impurity spin, and numerical calculations on a model example, show that these conditions may be satisfied by real spin impurities.