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

Abstract

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 Mn₂In₂Se_5, 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.