Van der Waals heterostructures with two-dimensional magnets offer a magnetic junction with an atomically sharp and clean interface. This attribute ensures that the magnetic layers maintain their intrinsic spin-polarized electronic states and spin-flipping scattering processes at a minimum level, a trait that can expand spintronic device functionalities. Here, using a van der Waals assembly of ferromagnetic Fe3GeTe2 with non-magnetic hexagonal boron nitride and WSe2 layers, we demonstrate electrically tunable, highly transparent spin injection and detection across the van der Waals interfaces. By varying an electrical bias, the net spin polarization of the injected carriers can be modulated and reversed in polarity, which leads to sign changes of the tunnelling magnetoresistance. We attribute the spin polarization reversals to sizable contributions from high-energy localized spin states in the metallic ferromagnet, so far inaccessible in conventional magnetic junctions. Such tunability of the spin-valve operations opens a promising route for the electronic control of next-generation low-dimensional spintronic device applications.
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K.-H.M., D.H.L., I.-H.L., D.H.H. and S.J. were supported by research grants for basic research funded by the Korea Research Institute of Standards and Science (no. KRISS-2020-GP20011059). J.E. and S.J. also acknowledge the support from the Basic Science Research Program through the National Research Foundation of Korea under grant nos NRF-2021R1A4A1031900 and NRF-2022R1A2C2008140. J.S. and J.S.K. were supported by the Institute for Basic Science through the Center for Artificial Low Dimensional Electronic Systems (IBS-R014-D1) and by the National Research Foundation of Korea (NRF-2022R1A2C3009731) and the Max Planck POSTECH/Korea Research Initiative (NRF-2022M3H4A1A04074153 and NRF-2020M3H4A2084417). S.-J.C. was also supported by the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter (EXC2147, project-id 390858490) and by the German Research Foundation (SPP1666 and SFB1170 ‘ToCoTronics’). C.K. acknowledges the support by the Institute for Basic Science in Korea (IBS-R009-G2).
The authors declare no competing interests.
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Min, KH., Lee, D.H., Choi, SJ. et al. Tunable spin injection and detection across a van der Waals interface. Nat. Mater. (2022). https://doi.org/10.1038/s41563-022-01320-3