Solution of the p(2×2) NiO() surface structure using direct methods

Erdman, Natasha; Warschkow, Oliver; Ellis, Donald E; Marks, Laurence D.

doi:10.1016/s0039-6028(00)00860-8

Cited by 35 publications

(29 citation statements)

References 33 publications

(62 reference statements)

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“…First, the top two surface layers were shifted to an on‐top position above the third layer to give a wurtzite‐like structure (O‐wurtzite) as observed for rocksalt CoO(111) 55. Second, a subsurface Ni atom in a (2 × 2) unit cell is transferred to an on top position above the surface O layer (Ni‐vac) 29. The composition of the four outermost layers is then given by Ni 1 –O 4 –Ni 3 –O 4 .…”

Section: Surface Structuresmentioning

confidence: 99%

“…By applying direct methods to re‐analyze the same thin film GIXD data of Ref. 26 it was concluded that the NiO(111) films are not terminated by an equal fraction of Ni‐ and O‐octopolar terraces but by an alternative vacancy structure (Ni‐vac) 29. This structure, however, is not charge neutral but exhibits an oxygen excess of Δ N O = 1/2 oxygen atoms per (1 × 1) surface unit cell.…”

Section: Introductionmentioning

confidence: 98%

“…Several conclusions of Barbier et al were put into question by Marks and coworkers [29,30]. By applying direct methods to re-analyze the same thin film GIXD data of Ref.…”

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confidence: 99%

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First‐principles study of the reconstruction and hydroxylation of the polar NiO(111) surface

Ebensperger

Meyer

2011

Physica Status Solidi (b)

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Density-functional theory (DFT) calculations have been combined with a thermodynamic formalism to determine a phase diagram of lowest-energy structures and compositions of the polar NiO(111) surface in equilibirum with oxygen, hydrogen, and water reservoirs at finite temperatures and pressures. Consistent with experiment we find that for a wide range of oxygen and hydrogen chemical potentials the surface is fully hydroxylated and shows a (1 Â 1) periodicity. At higher temperatures and H-poor conditions water can be removed from the surface and the two (2 Â 2) octopolar reconstructions become the thermodynamically most stable configurations. Other structures, which have been proposed on the basis of experimental data after high-temperature annealing, have to be considered to be kinetically limited metastable phases. In Opoor conditions no reduced surface structures are found to be thermodynamically stable. However, in O-rich environments and at low hydrogen chemical potential the surface can be oxidized by a partial removal of hydrogen or incorporation of additional oxygen. The structural motifs are closely related to the cadmium iodide structure of Ni(OH) 2 and NiO 2 .

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Section: Surface Structuresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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First‐principles study of the reconstruction and hydroxylation of the polar NiO(111) surface

Ebensperger

Meyer

2011

Physica Status Solidi (b)

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“…[23][24][25][26][27] The unreconstructed NiO (111) surface is again polar and expected to reconstruct; however, it can apparently be stabilized by a hydroxyl overlayer. Several model structures have been proposed that present a charge-neutral surface consistent with high-resolution surface data, 28,29 the most popular of which are based on arrangements of neutral pyramidal (NiO) 4 octopoles. 30 -32 Simulations also have been used to address the possibility of surface oxidation and nonstoichiometric regions.…”

Section: (2) Nio (111) Surfacementioning

confidence: 98%

Oxide–Oxide Interfaces: Atomistic and Density Functional Study of Cubic‐ZrO₂ (100) ‖ NiO (111)

Guo

Warschkow

Ellis

et al. 2001

Journal of the American Ceramic Society

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The cubic-ZrO 2 (100) ʈ NiO (111) interface provides an opportunity for comparison between atomic-scale measurements, atomistic simulations, and theoretical electronic structures. High-resolution electron microscopy indicates that the oxides share a common oxygen layer and that the small lattice strain is largely taken up by NiO near the interface. Using simple Coulomb plus Buckingham-type interatomic potentials, we are able to provide a more focused picture, revealing two types of boundary. The lowest energy interface is highly planar, almost ideal in structure; there is a second interface, of higher energy, that shows a rumpled structure with strain taken up by deformation of nickel chains. Depth profiling of atomic site energies permits calculation of interface versus bulk and surface energies, and it shows that the interface effects penetrate only two to three atomic layers. Embedded cluster density functional studies of bulk and interface-region sites permit the characterization of perturbations of electronic density around the boundaries.

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“…Due to a non-vanishing bulk dipole moment normal to the surface, these materials have an inherently high surface energy (Wolf 1992), but they may lower this energy by forming an air-stable reconstruction (Plass et al 1998;Barbier et al 2000aBarbier et al ,2000bErdman et al 2000;Finocchi et al 2004) or by adsorbing materials from the ambient environment (Lazarov et al 2005). In some cases, reconstruction is stable even under a bulk water layer.…”

Section: 18mentioning

confidence: 99%

Compact X-ray Light Source Workshop Report

Thevuthasan¹,

Evans²,

Terminello³

et al. 2012

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Executive SummaryThis report is the result of a workshop held in September 2011 that examined the utility of a compact x-ray light source (CXLS) in addressing many scientific challenges critical to advancing energy science and technology. The U.S. Department of Energy (DOE) and National Academy of Sciences (NAS) have repeatedly described the need for advanced instruments that "predict, control, and design the components of energetic processes and environmental balance," most notably in biological, chemical, environmental, and materials science. In numerous DOE and NAS reports, direct molecular-scale imaging and timedependent studies are seen as a powerful means to develop an atomistic-level understanding of scientific issues associated with current and future energy and environmental needs, including energy production and storage from both fossil-based and fossil-free sources and cleanup of government and industrial sites worldwide.One of the major enabling capabilities for meeting these needs is a high-brightness x-ray light source. The DOE report, Next-Generation Photon Sources for Grand Challenges in Science and Energy, identifies "spectroscopic and structural imaging of nano-objects (or nanoscale regions of inhomogeneous materials) with nanometer spatial resolution and ultimate spectral resolution" as one of the two aspects of energy science in which current and next-generation x-ray light sources will have the deepest and broadest impact. The report further stresses the power of direct observation in understanding transformational chemical processes. The report also discusses the importance of molecular "movies" of complex reactions that show bond breaking and reforming in natural time scales, along with the intermediate states to understand the mechanisms that govern chemical transformations. Existing accelerator-based x-ray sources have greatly extended capabilities in the time and space domain for scientific investigations in many disciplines. Despite these successes, a number of scientific challenges would benefit greatly from having an x-ray resource that has much of the attractive capability of these large machines but lends itself to operating in conjunction with other characterization tools in a correlative fashion. Such an integrated multiscale and multimodal approach could fully address the fundamental needs expressed by DOE's Office of Biological and Environmental Research (BER) in regards to understanding how genomic information is translated with confidence to redesign microbes, plants, or ecosystems (http://science.energy.gov/).Fortunately, recent advances in laser and super-cooled linear particle accelerator, or linac, technology have enabled development of a long-promised CXLS that uses inverse Compton scattering for generating x-rays. The new CXLS holds the promise of simultaneous energy tuning-from the soft to hard x-ray regime-as well as a pulsed structure closely coupled to the laser pulse duration of pico-to femtoseconds. With a projected brilliance equal to third-generation light sourc...

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Solution of the p(2×2) NiO() surface structure using direct methods

Cited by 35 publications

References 33 publications

First‐principles study of the reconstruction and hydroxylation of the polar NiO(111) surface

First‐principles study of the reconstruction and hydroxylation of the polar NiO(111) surface

Oxide–Oxide Interfaces: Atomistic and Density Functional Study of Cubic‐ZrO₂ (100) ‖ NiO (111)

Compact X-ray Light Source Workshop Report

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Solution of the p(2×2) NiO() surface structure using direct methods

Cited by 35 publications

References 33 publications

First‐principles study of the reconstruction and hydroxylation of the polar NiO(111) surface

First‐principles study of the reconstruction and hydroxylation of the polar NiO(111) surface

Oxide–Oxide Interfaces: Atomistic and Density Functional Study of Cubic‐ZrO2 (100) ‖ NiO (111)

Compact X-ray Light Source Workshop Report

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Product

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Oxide–Oxide Interfaces: Atomistic and Density Functional Study of Cubic‐ZrO₂ (100) ‖ NiO (111)