Controlling magnetism on metal surfaces with non-magnetic means: electric fields and surface charging

摘要

We review the state of the art of surface magnetic property control with nonmagnetic means,concentrating on metallic surfaces and techniques such as chargedoping or external electric field (EEF) application.Magnetoelectric coupling via EEFbased charge manipulation is discussed as a way to tailor single adatom spins,exchange interaction between adsorbates or anisotropies of layered systems.The mechanisms of paramagnetic and spindependent electric field screening and the effect thereof on surface magnetism are discussed in the framework of theoretical and experimental studies.The possibility to enhance the effect of EEF by immersing the target system into an electrolyte or ionic liquid is discussed by the example of substitutional impurities and metallic alloy multilayers.A similar physics is pointed out for the case of charge traps,metallic systems decoupled from a bulk electron bath.In that case the charging provides the charge carrier density changes necessary to affect the magnetic moments and anisotropies in the system.Finally,the option of using quasifree electrons rather than localized atomic spins for surface magnetism control is discussed with the example of Shockleytype metallic surface states confined to magnetic nanoislands.