EPJ B – Au and Cu as building blocks of high-density memory devices

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Published on 22 December 2010

Gold and copper atoms adsorbed on a NaCl surface behave as isolated atoms and complex electronic interactions with the surface are negligible. A study by a group of Brazilian researchers uses first-principles simulations to measure the electronic and magnetic properties of gold and copper atoms adsorbed on NaCl(001) surfaces, as well as the modifications in these properties upon charge injection.

The results presented in EPJ B show that neutral Au and Cu adatoms on NaCl(001) interact weakly with the ionic substrate. Magnetization values are close to those of the corresponding isolated atoms, with spatial distributions concentrated mainly around the adatoms. The magnetization comes from the unfilled s valence orbital of the adatoms, and its value drops to zero when a single electron is injected in the adatom and fills its s shell.

Quantifying and manipulating the magnetic moments of the adsorbed atoms is essential to exploit the these systems for producing ultra-high density magnetic memory devices. Experimentalists have already shown the feasibility of manipulating the adatom charge and magnetization with an STM tip.