Cluster nucleation and growth from a highly supersaturated adatom phase: Silver on magnetite

Roland Bliem, Rukan Kosak, Lukas Perneczky, Zbynek Novotny, Oscar Gamba, David Fobes, Zhiqiang Mao, Michael Schmid, Peter Blaha, Ulrike Diebold, Gareth S. Parkinson

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

The atomic-scale mechanisms underlying the growth of Ag on the (√2×√2)R45°-Fe3O4(001) surface were studied using scanning tunneling microscopy and density functional theory based calculations. For coverages up to 0.5 ML, Ag adatoms populate the surface exclusively; agglomeration into nanoparticles occurs only with the lifting of the reconstruction at 720 K. Above 0.5 ML, Ag clusters nucleate spontaneously and grow at the expense of the surrounding material with mild annealing. This unusual behavior results from a kinetic barrier associated with the (√2×√2)R45° reconstruction, which prevents adatoms from transitioning to the thermodynamically favorable 3D phase. The barrier is identified as the large separation between stable adsorption sites, which prevents homogeneous cluster nucleation and the instability of the Ag dimer against decay to two adatoms. Since the system is dominated by kinetics as long as the (√2×√2)R45° reconstruction exists, the growth is not well described by the traditional growth modes. It can be understood, however, as the result of supersaturation within an adsorption template system.

Original languageEnglish (US)
Pages (from-to)7531-7537
Number of pages7
JournalACS nano
Volume8
Issue number7
DOIs
StatePublished - Jul 22 2014

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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    Bliem, R., Kosak, R., Perneczky, L., Novotny, Z., Gamba, O., Fobes, D., Mao, Z., Schmid, M., Blaha, P., Diebold, U., & Parkinson, G. S. (2014). Cluster nucleation and growth from a highly supersaturated adatom phase: Silver on magnetite. ACS nano, 8(7), 7531-7537. https://doi.org/10.1021/nn502895s