Effects of MBE Growth on the Structural and Transport Properties of α- and γ-MnTe

MnTe is the subject of renewed attention due to its promising magnetic properties. MnTe has two prominent phases: α-MnTe and γ-MnTe, each having distinct crystalline and magnetic properties. In particular, α-MnTe has recently been shown to exhibit a novel class of magnetism known as altermagnetism, which may significantly broaden the frontiers for unconventional d-wave superconductivity and for novel spintronic devices.^1,2 However, the growth of pure single phase MnTe can be challenging. In this study we report on the controlled growth of MnTe using molecular beam epitaxy (MBE) in which several growth parameters including Te:Mn ratio growth temperature (T_g), substrates and buffer layers were varied to optimize the MnTe phases and properties. We show optimized conditions for pure, single-phase α-MnTe on InP(111)A, evidence of epitaxial α-MnTe (within a mixed phase sample) on InP(111)B using an In₂Se₃ buffer layer and the mixed MnTe phases grown on both InP(111)A and B. Evidence of the structural phases are probed using high resolution X-ray diffraction. Further analysis was conducted using pole figure to observe other crystal phases not easily seen in 2θ-ω scans; evidence of the mixed phases, even for residual quantities, was particularly clear in the pole figure analysis. Transport properties of these materials were probed to support the expected alter magnetic (antiferromagnetic-like behavior) in these samples.