Spin-orbit coupling proximity effect in MoS2/Fe3GeTe2 heterostructures

Layered two-dimensional (2D) magnet/semiconductor heterostructures combine spintronic and optoelectronic properties of constituent materials, leading to new magneto-optical and magnetoelectric phenomena such as spontaneous emission of helical light and enhanced Zeeman splitting in single photon emission. While prior focus was mostly on the magnetic proximity effect, where properties of 2D magnets are transferred to nonmagnetic 2D materials, the inverse effect of 2D semiconductors altering 2D magnets is much less understood. Here, we fabricated and studied van der Waals (vdW) heterostructures of 2D magnet Fe3GeTe2 (FGT) and 2D semiconductor MoS2. With reflectance magnetic circular dichroism, we found that the coercive field of MoS2-covered FGT reduces compared with uncovered FGT, agreeing well with our first-principles calculations. With its strong spin-orbit coupling (SOC), MoS2 effectively alters the crystal field of the adjacent FGT and its magnetic anisotropy. Furthermore, an unconventional two-step hysteresis loop emerges in MoS2/FGT as a result of the superposition of two regions of FGT: at the interface and away from the interface. Our experimental elucidation of the SOC proximity effect that MoS2 exerts on FGT provides fundamental understanding for the rational development of 2D magnet/semiconductor heterostructures.