Gate-tunable magnetic damping in van der Waals Heterostructures

Abstract

Active control of magnetic damping is a crucial capability for the development of low-power, tunable spintronic devices. In this work, we demonstrate that the intrinsic magnetic damping of 2D materials is highly sensitive to the position of the Fermi level relative to spin-orbit driven anti-crossings, or ``spin hot spots.'' Starting from a minimal multi-band model evaluated via Kamberský's breathing Fermi surface theory, we elucidate the fundamental role that energy gaps and band alignment play in governing magnetic dissipation. We then translate these theoretical insights to van der Waals heterostructures, proposing a concrete mechanism for strongly tunable magnetic damping via electrostatic gating. This concept is validated from first principles via density functional theory calculations on a realistic Fe$_3$GeTe$_2$/graphene heterostructure. Our calculations reveal that an out-of-plane electric field selectively shifts the relevant energy bands, enabling the modulation of the heterostructure's magnetic damping over several orders of magnitude. These findings establish a robust theoretical framework and a promising materials platform for electrically tunable magnetization dynamics.