High magnetic moments in manganese-doped silicon clusters

We report on the structural, electronic, and magnetic properties of manganese-doped silicon clusters cations, Si(n)Mn(+) with n=6-10, 12-14, and 16, using mass spectrometry and infrared spectroscopy in combination with density functional theory computations. This combined experimental and theoretical study allows several structures to be identified. All the exohedral Si(n)Mn(+) (n=6-10) clusters are found to be substitutive derivatives of the bare Si(n+1)(+) cations, while the endohedral Si(n)Mn(+) (n=12-14 and 16) clusters adopt fullerene-like structures. The hybrid B3P86 functional is shown to be appropriate in predicting the ground electronic states of the clusters and in reproducing their infrared spectra. The clusters turn out to have high magnetic moments localized on Mn. In particular the Mn atoms in the exohedral Si(n)Mn(+) (n=6-10) clusters have local magnetic moments of 4 μ(B) or 6 μ(B) and can be considered as magnetic copies of the silicon atoms. Opposed to other 3d transition-metal dopants, the local magnetic moment of the Mn atom is not completely quenched when encapsulated in a silicon cage.