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A Density Functional Study of Magnetism in Bare Gold Nano-clusters

R. J. Magyar·V. Mujica·M. Marquez·C. Gonzalez
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Abstract

Magnetism in bare uncapped gold nano-clusters is explored from a density functional theory perspective with scalar relativistic effects included via the pseudo-potential. The computed electronic structures of various nano-clusters reveal that permanent size-dependent spin-polarization appears without geometry relaxation for bare clusters even though bulk gold is diamagnetic. The polarized ground states for clusters are favorable due to the hybridization of the s and d orbitals, and bare octahedral clusters are expected to be magnetic for cluster sizes of approximately 38 atoms and larger. Much larger clusters will be diamagnetic when the surface-to-volume ratio is small and the core diamagnetism prevails. Moderate changes in the inter-atomic distances and cluster geometry are shown not to alter this conclusion. Contrary to LDA and EAM predictions, GGA and hybrid geometry optimizations reveal increased inter-atomic bond distances in bare gold clusters relative to the bulk lattice values. This expansion enhances the preexisting spin polarization.

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R. J. Magyar, V. Mujica, M. Marquez, C. Gonzalez. 2006-10-10. A Density Functional Study of Magnetism in Bare Gold Nano-clusters. https://arxiv.org/abs/cond-mat/0610267

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