Interface, bulk and surface structure of heteroepitaxial altermagnetic α-MnTe films grown on GaAs(111)

Journal Article · Wed Jul 09 20:00:00 EDT 2025 · Physical Review Materials

DOI: https://doi.org/10.1103/1dh1-mly1 · OSTI ID:2584447

Bey, Sara  ^[1]; Zhukovskyi, Maksym  ^[1]; Orlova, Tatyana ^[1]; Fields, Shelby  ^[2]; Lauter, Valeria  ^[3]; Ambaye, Haile  ^[3]; Ievlev, Anton  ^[3]; Bennett, Steven P.  ^[2]; Liu, Xinyu  ^[1]; Assaf, Badih A.  ^[1]

---

1. University of Notre Dame, IN (United States)
2. U.S. Naval Research Laboratory, Washington, DC (United States)
3. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Epitaxial MnTe films have recently seen a surge in research into their altermagnetic semiconducting properties. However, those properties may be extremely sensitive to structural and chemical modifications. We report a detailed investigation of the synthesis of the altermagnet α-MnTe on GaAs(111), which reveals the bulk defect structure of this material, the mechanism by which it releases strain from the underlying substrate, and the impact of oxidation on its surface. X-ray diffraction measurements show that α-MnTe layers with thicknesses spanning 45 to 640 nm acquire lattice parameters different from bulk, mostly due to thermal strain caused by the substrate rather than strain from the lattice mismatch. Through high-resolution transmission electron microscopy (TEM) measurement, we then unveil a misfit dislocation array at the interface, revealing the mechanism by which lattice strain is relaxed. TEM also reveals a stacking fault in the bulk, occurring along a glide plane parallel to the interface. The combination of TEM with polarized neutron reflectometry measurements finally reveals the impact of oxidation on the chemistry of the surface of uncapped MnTe. Furthermore, or findings highlight the subtle role of epitaxy in altering the structure of α-MnTe, providing potential opportunities to tune the altermagnetic properties of this material.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 2584447
• Journal Information: Physical Review Materials, Journal Name: Physical Review Materials Journal Issue: 7 Vol. 9; ISSN 2475-9953
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English