Atomic structure and bonding of the interfacial bilayer between Au nanoparticles and epitaxially regrown MgAl2O4 substrates

A unique metal/oxide interfacial bilayer formed between Au nanoparticles and MgAl2O4 substrates following thermal treatment is reported. Associated with the formation of the bilayer was the onset of an abnormal epitaxial growth of the substrate under the nanoparticle. According to the redistribution of atoms and the changes of their electronic structure probed across the interface by a transmission electron microscopy, we suggest two possible atomic models of the interfacial bilayer.