Observation of the Optical Phonons in α-MnTe films

Abstract: The altermagnetic materials have emerged as model systems 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 Neel temperature. Here, we report the molecular beam epitaxy (MBE) growth of high quality alpha MnTe thin films on GaAs(111)B substrates and provide a comprehensive analysis of the growth evolution and structural properties. Raman spectroscopy reveals multiple vibrational features of alpha MnTe including modes near 121, and 140 1/cm. Combined with first principles phonon calculations, these features are identified as the Raman-active phonons of the hexagonal NiAs type lattice. Our results show that the high crystalline quality of MBE grown alpha MnTe enables the complete experimental resolution of all symmetry allowed Raman active phonon modes, highlighting epitaxial alpha MnTe as a robust thin film platform for investigating altermagnetism and its lattice coupled excitations.