▎ 摘　　要

Electric field control of magnetism has become increasingly important for the next generation of graphene-based spintronic devices. We predict that the magnetic moment induced by chemisorbed H atoms on the top layer of a few-layer graphene system is tunable by an external electric field. Through accurate first-principles electronic structure calculations, we show that this magnetoelectric effect is negligible in one-layer graphene, but becomes pronounced in bilayer and trilayer graphene, saturating in magnitude in quadrilayer graphene. The effect is due to shifting of the Dirac cone of the pure graphene layers relative to the bands of the hydrogenated layer, induced by the external field. The calculated magnetoelectric coefficient (alpha) has values comparable to those found for ferromagnetic films or perovskite interfaces. The value of alpha was also used to identify a half-metallic state at low gate bias, which suggests a new class of spin-polarized materials based on hydrogenated multilayer graphene. Our results point to an experimentally feasible way to create a magnetoelectric coupling in graphene using the interplay between covalent functionalization and electric fields.