Study of the self-organization of spin-polarized atomic clusters on a solid rare gas surface

Exchange interaction is responsible for both covalent bonding and ferromagnetism in both localized and itinerant electron systems. Nevertheless, crystalline structures are not apparently affected by a change of electron magnetic state in most systems. In these systems, the exchange coupling constant J can be treated as constant to the first order during a magnetic transition. Coupling between the electron magnetic states and the atomic structure of matter has been studied over the last century. It was first taken up for explaining the magnetostriction of ferromagnetic metals in classical magnetics. A structural phase transition associated with magnetic ordering is mainly observed in systems with a degenerate ground state. The phenomenon has been explained in terms of the JahnTeller effects based on the symmetry considerations. If the orbital degeneracy is removed by coupling with a magnon, a structure of lower symmetry is stabilized in most cases.