Theory of Surface-Induced Magnetism in Adsorbed 3He Films: Indirect Exchange via Almost-Localized-Fermionic 3He Liquid

Abstract

A theory is proposed for the ferromagnetism observed in adsorbed ³He films. Applying a lattice model to liquid layers and allowing atoms to transfer between solid and liquid layers, we derive exchange constants for solid-layer atoms by perturbation theory. The extended Gutzwiller theory is used to treat strong correlation among atoms in liquid layers due to the hard-core. It is found that the nonuniformity of the sobstrate-³He interface causes the ferromagnetism and that the almost-localized-fermionic aspect of liquid-layer ³He is responsible for suppression of T_c at higher densities, discovered by H. Franco et al.