Surface Structures Far-from-Equilibrium

Personnel

Project Leader(s):
Michael Tringides

Principal Investigators:
Kai-Ming Ho, Myron Hupalo, Patricia Thiel, Michael Tringides, Cai-Zhuang Wang

Overview

This project focuses on low dimensional surface structures (ultrathin metallic films, islands, wires, etc.), especially in systems exhibiting quantum size effects (QSE). Since such structures are metastable and grown far from equilibrium, it is important to identify the optimal kinetic pathways. In turn, this requires a better understanding of many atomistic processes (e.g. surface diffusion, nucleation, coarsening) that define the kinetic pathway. In addition the properties of the grown structures (e.g. band structure, density-of-states) depend on the structure dimensions. This opens the possibility to control their potential uses in chemical reactivity and energy storage.

This interdisciplinary effort (physics, chemistry) is built upon a close interaction between theorists (Wang, Ho) and experimentalists (Tringides, Thiel, Hupalo). The scientists with the project have a strong background in film growth, coarsening, diffusion, nucleation, and overlayer structure analysis.

This projects objectives include:

  • Kinetics of growth. Certain systems with QSE exhibit anomalously fast aggregation kinetics, i.e. deposited atoms assemble very quickly into islands. We study and model the “window” in temperature and coverage parameter space where QSE-driven self organization is possible. These data are modeled to extract the controlling barriers. This understanding will be used to search for other systems where height uniformity exists.
  • QSE and chemisorption. We test the effect of QSE on chemisorption in several systems, using both experiment (STM/STS, XPS, HRLEED) and theory. These systems include oxygen and hydrocarbons on Ag nanostructures on Si(111); and oxygen and hydrogen on Pb and Mg nanostructures.

Highlights

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Publications

2012
Duguet T; Thiel P A . 2012. Chemical contrast in STM imaging of transition metal aluminides. Progress in Surface Science. 87:47-62. abstract
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Engstfeld A K; Hoster H E; Behm R J; Roelofs L D; Liu X J; Wang C Z; Han Y; Evans J W . 2012. Directed assembly of Ru nanoclusters on Ru(0001)-supported graphene: STM studies and atomistic modeling. Physical Review B. 86:085442. abstract
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Liu X J; Hupalo M; Wang C Z; Lu W C; Thiel P A; Ho K M; Tringides M C . 2012. Growth morphology and thermal stability of metal islands on graphene. Physical Review B. 86:081414. abstract
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Liu X J; Wang C Z; Hupalo M; Lu W C; Tringides M C; Yao Y X; Ho K M . 2012. Metals on graphene: correlation between adatom adsorption behavior and growth morphology. Physical Chemistry Chemical Physics. 14:9157-9166. abstract
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Binz S M; Hupalo M; Liu X J; Wang C Z; Lu W C; Thiel P A; Ho K M; Conrad E H; Tringides M C . 2012. High Island Densities and Long Range Repulsive Interactions: Fe on Epitaxial Graphene. Physical Review Letters. 109:026103. abstract
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Li T; Luo L; Hupalo M; Zhang J; Tringides M C; Schmalian J; Wang J . 2012. Femtosecond Population Inversion and Stimulated Emission of Dense Dirac Fermions in Graphene. Physical Review Letters. 108:167401. abstract
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Vlachos D; Kamaratos M; Foulias S D; Binz S; Hupalo M; Tringides M C . 2012. Lead growth on Si(111) surfaces reconstructed by indium. Journal of Physics-Condensed Matter. 24:095006. abstract
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Huang L; Wang C Z; Li M Z; Ho K M . 2012. Coverage-Dependent Collective Diffusion of a Dense Pb Wetting Layer on Si(111). Physical Review Letters. 108:026101. abstract
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2011
Liu X J; Wang C Z; Hupalo M; Lu W C; Thiel P A; Ho K M; Tringides M C . 2011. Fe-Fe adatom interaction and growth morphology on graphene. Physical Review B. 84:235446. abstract
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Gramlich M W; Hayden S T; Chen Y Y; Kim C; Conrad E H; Tringides M C; Miceli P F . 2011. Nonequilibrium behavior of the Pb wetting layer on Si(111)7x7. Physical Review B. 84:075433. abstract
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