Epitaxial growth of altermagnetic α-MnTe on GaAs(111)B substrate via molecular beam epitaxy.

The altermagnetic materials has emerged as a model system for studying spin-split electronic structures, yet controlled epitaxial growth on technologically relevant substrates remains challenging. Among the known candidates, MnTe stands out as a prominent altermagnetic material owing to its layered structure and high Néel temperature. Here, we report the molecular beam epitaxy (MBE) growth of high-quality α-MnTe thin films on GaAs(111)B substrates and provide a comprehensive analysis of the growth evolution and structural properties. Real-time reflection high-energy electron diffraction (RHEED) reveals a transition from three-dimensional island nucleation to streaky two-dimensional patterns, indicating the development of smooth epitaxial layers despite the large lattice mismatch. Raman spectroscopy confirms the formation of the hexagonal NiAs-type phase through the observation of the characteristic phonon modes at 121 cm⁻¹ and 140 cm⁻¹. X-ray diffraction measurements verify single-phase (0001) orientation, while scanning electron microscopy, energy-dispersive X-ray spectroscopy, and atomic force microscopy demonstrate uniform morphology, near-stoichiometric Mn:Te composition, and nanometer-scale surface roughness. These results establish a reliable growth protocol for α-MnTe on GaAs(111)B and provide a foundational platform for exploring strain-engineered altermagnetism and spin-dependent phenomena in epitaxial MnTe heterostructures.