Molecular Beam Epitaxy of Mn₂In₂Se₅ van der Waals Layers Using Mn Intercalation

The weak van der Waals (vdW) force in layered chalcogenide materials has enabled the growth of ternary chalcogenide layers using unconventional approaches. Here, we report the molecular beam epitaxy (MBE) growth of Mn2In2Se5, a spin glass material with a high level of magnetic frustration, through the heterointegration of MnSe on In2Se3. Directly depositing α-MnSe on the vdW In2Se3 layers results in Mn intercalation, transforming the In2Se3 layer into Mn2In2Se5. Large growth windows, including substrate temperatures from 250 to 450 °C and Se:Mn flux ratios of 1.1–3.1, have been identified for the intercalation process. With an optimized MnSe deposition time, smooth, single-crystalline, and (0001)-oriented Mn2In2Se5 layers with a root-mean-square roughness of 1.5 nm can be synthesized. Further extending the MnSe deposition time results in the growth of uniform rock-salt structured α-MnSe(111) layers with a thickness of up to 8 nm and a narrow full width at half-maximum of 0.35° in MnSe(222) XRD rocking curves. This report presents a unique approach for the growth of uniform and single-crystalline Mn2In2Se5 vdW layers using MBE and potentially opens a pathway for synthesis of ternary vdW chalcogenides by intercalation of new atomic species in binary vdW chalcogenides.