Unusual Structure and Magnetism in MnO Nanoclusters

We report an unusual structural and magnetic evolution in stoichiometric MnO nanoclusters by an extensive and unbiased search through the potential energy surface within density functional theory. The $(MnO)_n$ nanoclusters adopt two-dimensional structures in size ranges in which $Mn_n$ nanoclusters are three-dimensional and regardless of the size of the nanocluster, the magnetic coupling is found to be antiferromagnetic, and is strikingly different from Mn-based molecular magnets. Both of these features are explained through the inherent electronic structures of the nanoclusters.