Epitaxial growth of 2D manganese dibromide thin films on Au(111) with buffering overlayers

Abstract

As promising candidates for two-dimensional (2D) magnetic semiconductors, layered transition metal halides (TMHs) have attracted increasing interest due to their diverse insulating bandgaps and magnetic properties. Here, we report the epitaxial growth of atomically thin MnBr₂ films on Au(111) by molecular beam epitaxy (MBE). Scanning tunneling microscopy (STM) reveals the initial formation of different buffering layers with distinct atomic structures on the Au(111) surface, followed by the subsequent growth of MnBr₂ layers. X-ray photoelectron spectroscopy (XPS) confirms that Mn atoms are in different coordination environments in the buffering layers (MnBr_x, x < 2) from MnBr₂ crystals. The electronic properties of MnBr₂ thin films with different thicknesses are investigated by scanning tunneling spectroscopy (STS) and density functional theory (DFT) calculations, showing that the electronic band structures are nearly independent of the thickness and the Au(111) substrate. This study provides a better insight into the growth behavior and interfacial properties of 2D layered TMHs on metal substrates.