| 09:30-10:40 | Fr1: Thermal transport, friction, and dissipation |
| 10:40-11:20 | Coffee break |
| 11:20-13:00 | Fr2: Catalysis and single-molecule chemistry |
| 13:00-14:00 | Closing session with poster prize ceremony, G. Benedek |
Chair: A. Mugarza, Barcelona, Spain
Contributed talk
Characterisation of monolayer MgO films on Ag(100)
1IMEM-CNR, U.O.S. Genova, Via Dodecaneso 33, 16146 Genova, Italy
2DIFI Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova, Italy
The ability to engineer nearly perfect ultrathin oxide layers, up to the limit of monolayer thickness, is a key issue for nano-technological applications in fields as catalysis, corrosion protection, micro- and nano-electronics, sensoristics, spintronics, drug delivery, etc. [1]. We faced the difficult and important case of ultrathin MgO films on Ag(100), for which no extended and well-ordered layers could so far be produced in the monolayer limit. The stoichiometric and morphological characteristics of MgO monolayers were shown to depend critically on growth parameters as temperature (Tg) [2], O2 partial pressure and Mg evaporation rate [3] during reactive deposition. However, contrasting data are present in literature with respect both to the optimal Tg [2,4] and to the island morphology and orientation [5,6].
Recently we demonstrated [7] that the final morphology of monolayer MgO/Ag(100) films depends not only on the usual growth parameters but also on after-growth treatments - in particular on the cooling rate after growth – which control so far neglected thermodynamics constrains. We succeeded thus in tuning the shape of the oxide films from irregular, nm-sized, monolayer thick islands, to slightly larger, perfectly squared bilayer islands, to extended monolayers limited apparently only by substrate steps. In my talk I will present these new results and I will revise previous finding by our group in light of the new information available.
[1] G. Pacchioni, H. J. Freund, Chem. Rev. 113, 4035 (2013)
[2] A. Ouvrard et al., J. Phys. Chem. C 115, 8034 (2011)
[3] G. Cabailh et al., J. Phys. Chem. A 115, 7161 (2011)
[4] H. J. Shin et al., Nat. Mat. 9, 442 (2009)
[5] S. Schintke et al., Phys. Rev. Lett. 87, 276801 (2001)
[6] S. Valeri et al., Phys. Rev. B. 65, 245410 (2002)
[7] J. Pal, M. Smerieri, E. Celasco, L. Savio, L. Vattuone, M. Rocca, Phys. Rev. Lett. 112, 126102 (2014)