Molecular beam epitaxy of antiferromagnetic (MnBi₂Te₄)(Bi₂Te₃) thin films on BaF₂ (111)

The layered van der Waals compounds (⁠$MnBi2Te4$⁠)(⁠$Bi2Te3$⁠) were recently established as the first intrinsic magnetic topological insulators. We report a study on the epitaxial growth of $(MnBi2Te4)m(Bi2Te3)n$ films based on the co-deposition of MnTe and $Bi2Te3$ on $BaF2$ (111) substrates. X-ray diffraction and scanning transmission electron microscopy evidence the formation of multilayers of stacked $MnBi2Te4$ septuple layers and $Bi2Te3$ quintuple layers with a predominance of $MnBi2Te4$⁠. The elemental composition and morphology of the films is further characterized by x-ray photoemission spectroscopy and atomic force microscopy. X-ray magnetic circular and linear dichroism spectra are comparable to those obtained for $MnBi2Te4$ single crystals and confirm antiferromagnetic order in the films.