Iron Opposes Mergers
Scientists have discovered that the growth of iron on graphene — a one atom thick layer of carbon — occurs in an unusual way. For other metals the first atoms to arrive form small clusters on the graphene surface, and then the clusters migrate across the surface, seemingly at random. Whenever two clusters encounter each other, they merge to form a larger cluster, which moves a little slower. Growing these larger clusters is important for making electronic connections to graphene for microelectronic applications. Iron is different in that lots of small islands form, but they do not tend to merge together even as the temperature is increased. This was shown by imaging the nano-sized islands as iron was deposited, and following the islands as a function of both time and temperature. Simulations of iron on graphene support the conclusion that the islands actually repel each other. This finding is significant because graphene-based computer data storage and other nanomagnetic applications are possible if magnetic metals, like iron, can be grown controllably on graphene with a high island density.
- S. M. Binz, M. Hupalo, Xiaojie Liu, C. Z. Wang, Wen-Cai Lu, P. A. Thiel, K. M. Ho, E. H. Conrad and M. C. Tringides. High Island Densities and Long Range Repulsive Interactions: Fe on Epitaxial Graphene. Physical Review Letters, 2012, 109, 026103. DOI: 10.1103/PhysRevLett.109.026103