Emergent ferromagnetism in altermagnetic candidate MnTe films grown on InP (111)*

To push into new generations of spintronic devices requires understanding new magnetic phenomena and also how to control both known and emerging material platforms as high-quality epitaxial thin films. Specifically, altermagnets are a new phase that is predicted to exhibit a strong spin splitting of the band structure, which can form the basis for new spintronic applications. MnTe, a candidate altermagnet, is a room-temperature antiferromagnet (TN ≈ 310 K) semiconductor (energy gap of order 1 eV) with a NiAs structure. Here, we present results on the molecular beam epitaxy growth and properties of MnTe/InP(111). Using polarized neutron reflectivity and magnetotransport, we find that there is emergent ferromagnetic behavior likely driven by a combination of charge transfer and strain. The ferromagnetic component is likely a slight canting of the bulk-like A-type antiferromagnetic state, as seen by neutron diffraction. This high level of tunabililty of MnTe opens the door to tailoring interlayer magnetic interactions in this layered material system. Together these results provide a potential mechanism of tuning antiferromagnetic ordering for applications in high-speed, next-generation spintronics.