Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9594622 | Surface Science | 2005 | 7 Pages |
Abstract
The morphology of ultrathin epitaxial MgO layers reactively grown at 470Â K and at 1Â MLÂ minâ1 on Ag(0Â 0Â 1) was investigated by scanning tunnelling microscopy (STM). At deposition of 1.3 and 2.6Â ML, square MgO domains of about (10Â ÃÂ 10)Â nm2 form. On mono- and bi-layer domains, edges are mainly oriented along the ã1Â 1Â 0ã oxide direction, corresponding to polar (P) borders, while on multi-layer domains also non-polar (NP) borders appear, corresponding to the ã1Â 0Â 0ã orientation. By using periodic models and ab initio DFT calculations, the energetics of the two orientations was studied. Interaction with the metal substrate was found to strongly reduce the instability of P borders, although not enough to make the two orientations equally stable. The results are discussed, also with reference to conflicting experimental evidence from other laboratories.
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
A.M. Ferrari, S. Casassa, C. Pisani, S. Altieri, A. Rota, S. Valeri,