Scanning tunneling microscopy and density functional theory study of initial bilayer growth of Ag films on NiAl(110)

Ünal, Barış; Qin, F.; Han, Yong; Liu, Da‐Jiang; Jing, Dapeng; Layson, Anthony R.; Jenks, Cynthia J.; Evans, James W.; Thiel, Patricia A.

doi:10.1103/physrevb.76.195410

Cited by 32 publications

(63 citation statements)

References 67 publications

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“…In other words, one expects annealing to heal the damage induced by sputtering and smoothen the surface. Figure 6 shows that this expectation is met for three other metallic samples that have been studied in our laboratory: (1) the (110) surface of a crystalline binary alloy, NiAl [15], …”

Section: Philosophical Magazine 2881mentioning

confidence: 91%

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Weak bonding of Zn in an Al-based approximant based on surface measurements

Yuen

Ünal

Jing

et al. 2010

Philosophical Magazine

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We have studied two surfaces of a new Al-Pd-Zn approximant using mass spectrometry, X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). Zn is bonded weakly in this approximant, perhaps as weakly as in elemental Zn. This is based upon three observations: (1) the low vapor pressure of Zn above the approximant (detectable in the gas phase at 600 K), (2) preferential sputtering of Zn (contrary to the usual preferential sputtering of Al in Al-rich quasicrystals), and (3) preferential surface segregation of Zn. We further show that preferential segregation -and perhaps incipient evaporation -causes the surface to roughen, preventing it from forming a terrace-step morphology. Finally, our data show that at low O2 pressures, Al oxidizes. In air, Zn oxidizes as well. All results and conclusions are similar for the two-fold and pseudo-10-fold surfaces. RightsThis article is (co-)authored by an employee of the United States Government and is not subject to copyright in the United States (17 U.S.C. §105). Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden.The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. We have studied two surfaces of a new Al-Pd-Zn approximant using mass spectrometry, X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). Zn is bonded weakly in this approximant, perhaps as weakly as in elemental Zn. This is based upon three observations: (1) the low vapor pressure of Zn above the approximant (detectable in the gas phase at 600 K), (2) preferential sputtering of Zn (contrary to the usual preferential sputtering of Al in Al-rich quasicrystals), and (3) preferential surface segregation of Zn. We further show that preferential segregation -and perhaps incipient evaporation -causes the surface to roughen, preventing it from forming a terrace-step morphology. Finally, our data show that at low O 2 pressures, Al oxidizes. In air, Zn oxidizes as well. All results and conclusions are similar for the two-fold and pseudo-10-fold surfaces. Philosophical MagazineVol. 91, Nos. 19-21, 1-21 July 2011, 2879-

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Section: Philosophical Magazine 2881mentioning

confidence: 91%

“…The main UHV chamber, used for STM and XPS, has been described elsewhere [15]. A second, smaller vacuum chamber was used to measure the effective pressure of Zn as a function of sample temperature.…”

Section: Methodsmentioning

confidence: 99%

Weak bonding of Zn in an Al-based approximant based on surface measurements

Yuen

Ünal

Jing

et al. 2010

Philosophical Magazine

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“…2. ) In contrast, the height of first level Ag islands from line profiles is significantly larger: 0.33 nm at 200 K and 0.32 nm at 300 K (independent of tip bias), consistent with a bilayer fcc(110) structure (22). (See Fig.…”

Section: Au On Nial(110) and Comparison With Ag On Nial(110)mentioning

confidence: 92%

“…1 C and D.) The height of second level Ag islands (populated above 40% coverage at 200 K) is 0.29 nm, again corresponding to a bilayer fcc(110) structure (22). Thus, a first key observation is the strongly different vertical island structures for Au and Ag.…”

Section: Au On Nial(110) and Comparison With Ag On Nial(110)mentioning

confidence: 95%

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Self-assembly of metal nanostructures on binary alloy surfaces

Duguet

Han²,

Yuen

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Deposition of metals on binary alloy surfaces offers new possibilities for guiding the formation of functional metal nanostructures. This idea is explored with scanning tunneling microscopy studies and atomistic-level analysis and modeling of nonequilibrium island formation. For Au/NiAl(110), complex monolayer structures are found and compared with the simple fcc(110) bilayer structure recently observed for Ag/NiAl(110). We also consider a more complex codeposition system, ðNi þ AlÞ∕NiAlð110Þ, which offers the opportunity for fundamental studies of self-growth of alloys including deviations for equilibrium ordering. A general multisite lattice-gas model framework enables analysis of structure selection and morphological evolution in these systems.S elf-assembly involves the autonomous organization of components into structures (1). This process requires mobility of aggregating components, and usually occurs on smooth surfaces or in fluids. Some degree of relaxation in the aggregated state is typically also operative. Self-assembly can be manifested in either complex equilibrium structures, e.g., reflecting competing interactions, or in far-from-equilibrium growth structures (1). The latter can be very different and more diverse than the equilibrium forms (2). Significantly, self-assembly provides a practical strategy for creating ensembles of nanostructures with unique size and shape dependent properties, a central goal of nanotechnology.A broad range of systems self-assemble, spanning hard and soft matter, with a wide variety of interactions and component sizes. We consider the formation of metal nanostructures motivated by applications ranging from catalysis to plasmonics (3-5). Our specific focus is vapor deposition of metal atoms on single-crystal metal surfaces under the well controlled conditions of ultrahigh vacuum (UHV). This process leads to the self-assembly of metal nanostructures and growth of epitaxial metal films. Here, the nonaggregated components are rapidly diffusing adsorbed atoms (adatoms) which assemble into islands. Relaxation in the aggregated state can be achieved via diffusion of adatoms along island edges or via detachment-reattachment. Understanding these processes on the atomic scale facilitates guided formation of functional nanostructures with tailored morphologies and (for alloys) compositions. Ideally, control over formation allows tuning of desired properties, e.g., for heterogeneous catalysis (6).Despite the complexity of self-assembly processes, significant advances are being made in the development of predictive models even in soft material systems (7). Our focus on epitaxial growth on perfect single-crystal surfaces (hard materials) under UHV has a special advantage in facilitating extremely detailed and realistic atomistic-level modeling. Localization of adatoms to a periodic array of adsorption sites enables the use of lattice-gas (LG) models for which nonequilibrium evolution can be efficiently analyzed on the appropriate time-and length-scales via kinetic Monte Carlo (KMC)...

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First-principles study of the Al(001)/Al3Ti(001) interfacial properties

Yang

2012

Computational Materials Science

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Scanning tunneling microscopy and density functional theory study of initial bilayer growth of Ag films on NiAl(110)

Cited by 32 publications

References 67 publications

Weak bonding of Zn in an Al-based approximant based on surface measurements

Weak bonding of Zn in an Al-based approximant based on surface measurements

Self-assembly of metal nanostructures on binary alloy surfaces

First-principles study of the Al(001)/Al3Ti(001) interfacial properties

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