Strain and electric field modulation of Schottky barrier height and magnetism in Fe2C/NiO2 van der Waals heterostructures

Van der Waals-stacked two-dimensional magnetic heterojunctions of intrinsic ferromagnets hold great promise for advanced spintronics. We explore the electronic and magnetic properties of Fe 2 C/NiO 2 vdWH via first-principles calculations. Computational results reveal that the Fe 2 C/NiO 2 vdWH exhibits ferromagnetic characteristics with an out-of-plane easy axis. Moreover, the heterostructure demonstrates a high Curie temperature( Tc) of 624 K, significantly surpassing the 511 K of Fe₂C monolayer. A tensile strain of Δd = 0.5 Å transitions the Fe 2 C/NiO 2 vdWH interfacial contact from Ohmic to Schottky contact, while a compressive strain of Δd = −0.5 Å, the interfacial contact shifts from Schottky to Ohmic contact. Notably, a compressive strain of Δd = −0.6 Å significantly boosts Tc from 624 K to 2004 K, and a Dirac point appears at the high-symmetry K point in the Fe 2 C/NiO 2 vdWH band structures. The application of vertical strain alters the relative position between the Dirac point and the Fermi level, which is accompanied by a change in the doping type of the Fe₂C (NiO₂) monolayer and an increase in its carrier concentration. The electronic and magnetic characteristics of Fe 2 C/NiO 2 vdWHs can be efficiently tuned by applying electric fields and vertical strain, offering promising application prospects in Spintronic storage and computation.