sp magnetism in clusters of gold-thiolates

TL;DR

This study uses first-principles calculations to explore how thiolate bonds influence magnetism in gold clusters, revealing size-dependent spin moments linked to S-Au bonding and potential for controlling nanoparticle magnetism.

Contribution

It provides new insights into the size-dependent magnetic properties of gold-thiolate clusters and the role of S-Au bonds in inducing and controlling magnetism.

Findings

Odd-numbered gold clusters exhibit a spin moment of 1 μB.

Even-numbered clusters have zero spin moment.

Magnetism is localized below the surface and can be tuned by thiolate coverage.

Abstract

Using calculations from first principles, we herein consider the bond made between thiolat e with a range of different Au clusters, with a particular focus on the spin moments inv olved in each case. For odd number of gold atoms, the clusters show a spin moment of 1.~ $\mu_B$. The variation of spin moment with particle size is particularly dramatic, with t he spin moment being zero for even numbers of gold atoms. This variation may be linked w ith changes in the odd-even oscillations that occur with the number of gold atoms, and is associated with the formation of a S-Au bond. This bond leads to the presence of an extra electron that is mainly sp in character in the gold part. Our results sugg est that any thiolate-induced magnetism that occurs in gold nanoparticles may be locali zed in a shell below the surface, and can be controlled by modifying the coverage of the thiolates.