VLEED from a ZnO(0001) substructure

Møller, Preben J.; Komolov, S. A.; Lazneva, E. F.

doi:10.1016/0039-6028(94)91560-1

Cited by 23 publications

(18 citation statements)

References 13 publications

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“…The positions of the narrow, sharp, solitary and violent peaks rely both on the crystal geometry of the surface and on the incident and azimuth angles of the electron beams. 19,20 The sharp peaks converge into the thresholds of emerging new beams inside the crystal, as found from the O-Ru(0001), 21 Cu(111) and Ni(111) 12 and the ZnO(0001) 11 surfaces. These features are suggested as being issued from the energy-band structure.…”

Section: Vleed Stm and Pesmentioning

confidence: 68%

“…[8][9][10][11][12][13][14] The scattering of VLEED beams from light adsorbates is often stronger, even comparable to the substrate host atoms, and this can lead to improved knowledge of the adsorbates positions 15 as well as the valences of individual surface atoms with the assistance of an appropriate model. This is due to bond formation that modifies the electronic structures of the negative ions of the light adsorbates and alters the valences of the host atoms.…”

Section: Vleed Stm and Pesmentioning

confidence: 99%

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O–Cu(001): I. BINDING THE SIGNATURES OF LEED, STM AND PES IN A BOND-FORMING WAY

Sun

2001

Surf. Rev. Lett.

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This work consists of two sequential parts, which review the advances in uncovering the capacity of VLEED, STM and PES in revealing the nature and kinetics of oxidation bonding and its consequences for the behavior of atoms and valence electrons at a surface; and in quantifying the O-Cu(001) bonding kinetics. The first part describes the model in terms of bond making and its effect on the valence DOS and on the surface potential barrier (SPB) for surfaces with chemisorbed oxygen. One can replace the hydrogen in a H2O molecule with an arbitrary less electronegative element and extend the M2O to a solid surface with Goldschmidt contraction of the bond length, which formulates a specific oxidation surface with identification of atomic valences and their correspondence to the STM and PES signatures. As consequences of bond making, oxygen derives four additional DOS features in the valence band and above, i.e. O-M bonding (∼ −5 eV), oxygen nonbonding lone pairs (∼ −2 eV), holes (≤ EF ), and antibonding metal dipoles (≥ EF ), in addition to the hydrogen-bond-like formation. The evolution of O −1 to O −2 transforms the CuO2 pairing off-centered pyramid in the c(2 × 2)-2O −1 into the Cu3O2 pairing tetrahedron in the (2 √ 2 × √ 2)R45 • -2O −2 phase on the Cu(001) surface. The new decoding technique has enabled the model to be justified and hence the capacity of VLEED, PES and STM to be fully uncovered in determining simultaneously the bond geometry, the SPB, the valence DOS, and their interdependence. * Fax: 65 6792 0415.

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Section: Vleed Stm and Pesmentioning

confidence: 68%

Section: Vleed Stm and Pesmentioning

confidence: 99%

O–Cu(001): I. BINDING THE SIGNATURES OF LEED, STM AND PES IN A BOND-FORMING WAY

Sun

2001

Surf. Rev. Lett.

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“…LEED experiments 10,13 show that there is an overall 6-fold symmetry on the thermally etched surface. This can be interpreted as the surface being stepped, i.e., there are plateaus of different heights which will act to eliminate the dipole.…”

Section: Resultsmentioning

confidence: 99%

“…This can be interpreted as the surface being stepped, i.e., there are plateaus of different heights which will act to eliminate the dipole. The data have been interpreted 13 in terms of pyramids, built up by atomic rows. If these are randomly distributed, the 6-fold pattern can be explained (another possibility would be that every Zn ion relaxes to be in the same plane as the oxygens).…”

Section: Resultsmentioning

confidence: 99%

“…This has been explained 12 by assuming a randomly stepped surface with a 60°rotation between adjacent terraces or in terms of hexagonal pits of unknown dimensions. 13 Since the (0001) surface is polar it must reconstruct or relax to eliminate the dipole across the crystal. Indeed, STM pictures of the (0001) surface show a rough landscape, 14 far from the idealized picture of well-ordered hexagonal pits reported from the LEED experiments.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen Dissociation on Reconstructed ZnO Surfaces

Nyberg¹,

Nygren²,

Pettersson³

et al. 1996

J. Phys. Chem.

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Atomistic modeling of reconstructions and relaxation of the nonpolar (101 h0) and (112 h0) ZnO surfaces has been performed to obtain more realistic surface structures for embedded cluster quantum chemical calculations of the reactivity of ZnO toward H 2 dissociation. Only small differential geometrical effects are found for the cation and anion top-layer relaxations. Both surfaces are found to be unreactive toward H 2 dissociation. For the polar, Zn-terminated (0001) surface several different reconstructions were studied; the lowest surface energy was obtained for a 4×4 reconstruction containing single-step plateaus and valleys. The highest exothermicity was found for H 2 dissociation over a corner site, involving a low-coordination oxygen, on the plateau. The edge sites on the plateau also lead to exothermic reactions, while the regular sites between plateaus are unreactive. The determining factor for the exothermicity is the coordination of the anion, but the ionization potential at the anion site also shows a correlation with the exothermicity. No cooperative effects were found. The vibrational frequencies were computed in qualitative agreement with experiment for the O-H vibration, while the strong experimental Zn-H peak at 1710 cm -1 has not been reproduced. The quantum chemically computed chargeson the ions are found to vary with coordination and position; this could have an effect on the atomistic modeling which presently does not include coordination-dependent terms in the potentials. Using an unembedded, gas-phase ZnO unit as a model leads to unrealistically high reaction energies; this is also the case if reconstruction of the (0001) surface is neglected. This demonstrates the need to develop realistic embedding schemes.

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5.8.21 Pt

Moritz

2015

Physics of Solid Surfaces

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VLEED from a ZnO(0001) substructure

Cited by 23 publications

References 13 publications

O–Cu(001): I. BINDING THE SIGNATURES OF LEED, STM AND PES IN A BOND-FORMING WAY

O–Cu(001): I. BINDING THE SIGNATURES OF LEED, STM AND PES IN A BOND-FORMING WAY

Hydrogen Dissociation on Reconstructed ZnO Surfaces

5.8.21 Pt

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