Manipulating Magnetic Damping of Fe/GeTe Heterostructures by Band Engineering

Understanding and manipulating magnetic damping, particularly in magnetic heterostructures, is crucial for fundamental research, versatile engineering, and optimization. Although magnetic damping can be enhanced by the band hybridization between ferromagnetic and nonmagnetic materials at the interface, the contribution of individual subbands on the hybridized bands to magnetic damping is fully unexplored. Here, it is found that magnetic damping α_eff is modified by the Fermi level in Fe/GeTe heterostructures via Bi doping. By combining angle-resolved photoemission spectroscopy and density functional theory calculations, the enhancement of damping originated from the strongly hybridized band structures between Fe and the surface Rashba bands of GeTe are unveiled. More interestingly, the Fermi level modulates the density of states (DOS) ratio between the subbands of GeTe and the total DOS of hybridized states, which is directly proportional to the magnetic damping. This work gives an insightful physical understanding of the magnetic damping influenced by the hybridized band structures and opens a novel avenue to manipulate magnetic damping by band engineering.