1. Nanoscale "Quantum" Islands on Metal Substrates: Microscopy Studies and Electronic Structure Analyses.
- Author
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Yong Han, Ünal, Bariş, Dapeng Jing, Thiel, Patricia A., Evans, James W., and Da-Jiang Liu
- Subjects
NANOTECHNOLOGY ,SUBSTRATES (Materials science) ,SCANNING tunneling microscopy ,ELECTRONIC structure ,MORPHOLOGY ,FREE electron theory of metals ,DENSITY functionals ,THERMODYNAMICS ,BINARY metallic systems - Abstract
Confinement of electrons can occur in metal islands or in continuous films grown heteroepitaxially upon a substrate of a different metal or on a metallic alloy. Associated quantum size effects (QSE) can produce a significant height-dependence of the surface free energy for nanoscale thicknesses of up to 10-20 layers. This may suffice to induce height selection during film growth. Scanning STM analysis has revealed remarkable flat-topped or mesa-like island and film morphologies in various systems. We discuss in detail observations of QSE and associated film growth behavior for Pb/Cu(111), Ag/Fe(100), and Cu/fcc-Fe/Cu(100) [A/B or A/B/A], and for Ag/NiAl(110) with brief comments offered for Fe/Cu
3 Au(001) [A/BC binary alloys]. We also describe these issues for Ag/5-fold i-Al-Pd-Mn and Bi/5-fold i-Al-Cu-Fe [A/BCD ternary icosohedral quasicrystals]. Electronic structure theory analysis, either at the level of simple free electron gas models or more sophisticated Density Functional Theory calculations, can provide insight into the QSE-mediated thermodynamic driving force underlying height selection. [ABSTRACT FROM AUTHOR]- Published
- 2010
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