Simulation of reconstructions of the polar ZnO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo>(</mml:mo><mml:mn>0001</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:math>surfaces

Meskine, Hakim; Mulheran, Paul A.

doi:10.1103/physrevb.84.165430

Cited by 30 publications

(9 citation statements)

References 31 publications

(26 reference statements)

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“…Noteworthy is that although the clean surface at this condition is expected to be only metastable, since polarity is not yet removed, it serves to indicate trends of the consequences on the electronic structure of the hydrogen adsorption at specific sites. Nevertheless, we note that the experimental valence-band features are quite well described by the calculations whereas the upper part is related to the O 2p orbitals and the lower part to the Zn 3d orbitals, which are also consistent with earlier reports in the literature [36][37][38][39].…”

Section: Resultssupporting

confidence: 92%

Hydrogen-induced metallization on the ZnO(0001) surface

et al. 2018

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Section: Resultssupporting

confidence: 92%

Hydrogen-induced metallization on the ZnO(0001) surface

et al. 2018

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“…The majority of the eigenfrequencies lowered marginally as a consequence of the structural change. Second, 5% of Cu ions were replaced with Zn ions, and Zn +2 -core O −2.869 -shell BMB parameters A = 499.6 eV, ρ = 0.359Å, C = 0 were used [67]. This additionally lowered the phonon frequencies, with calculated values reported in [54].…”

Section: -7mentioning

confidence: 99%

Influence of nonmagnetic Zn substitution on the lattice and magnetoelectric dynamical properties of the multiferroic material CuO

et al. 2014

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Dynamic magnetoelectric coupling in the improper ferroelectric Cu 1−x Zn x O (x = 0, x = 0.05) was investigated using terahertz time-domain spectroscopy to probe electromagnon and magnon modes. Zinc substitution was found to reduce the antiferromagnetic ordering temperature and widen the multiferroic phase, under the dual influences of spin dilution and a reduction in unit-cell volume. The impact of Zn substitution on lattice dynamics was elucidated by Raman and Fourier-transform spectroscopy, and shell-model calculations. Pronounced softenings of the A u phonons, active along the direction of ferroelectric polarization, occur in the multiferroic state of Cu 1−x Zn x O, and indicate strong spin-phonon coupling. The commensurate antiferromagnetic phase also exhibits spin-phonon coupling, as evidenced by a Raman-active zone-folded acoustic phonon, and spin dilution reduces the spin-phonon coupling coefficient. While the phonon and magnon modes broaden and shift as a result of alloy-induced disorder, the electromagnon is relatively insensitive to Zn substitution, increasing in energy without widening. The results demonstrate that electromagnons and dynamic magnetoelectric coupling can be maintained even in disordered spin systems.

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“…Specifically, as previously discussed by [57] and subsequently by other researchers [47,62,29], when there is a dipole moment in the repeat unit normal to the surface of an ionic crystal, the electrostatic energy diverges, and the surface energy goes to infinity. Because of this, there are typically three techniques that are employed in atomistic simulations to eliminate this effect: charge compensation (CC) [29,16], surface reconstruction (SR) [40,18] and surface passivation (SP) or adsorption [54]. These stabilization techniques are utilized because such reconstructions and passivation have been observed experimentally [34,33,19], and they have also been widely used in first principles calculations [14,61].…”

Section: Introductionmentioning

confidence: 99%

Surface effects on the piezoelectricity of ZnO nanowires

Dai

Park

2013

Journal of the Mechanics and Physics of Solids

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We utilize classical molecular dynamics to study surface effects on the piezoelectric properties of ZnO nanowires as calculated under uniaxial loading. An important point to our work is that we have utilized two types of surface treatments, those of charge compensation and surface passivation, to eliminate the polarization divergence that otherwise occurs due to the polar (0001) surfaces of ZnO. In doing so, we find that if appropriate surface treatments are utilized, the elastic modulus and the piezoelectric properties for ZnO nanowires having a variety of axial and surface orientations are all reduced as compared to the bulk value as a result of polarization-reduction in the polar [0001] direction. The reduction in effective piezoelectric constant is found to be independent of the expansion or contraction of the polar (0001) surface in response to surface stresses. Instead, the surface polarization and thus effective piezoelectric constant is substantially reduced due to a reduction in the bond length of the Zn-O dimer closest to the polar (0001) surface. Furthermore, depending on the nanowire axial orientation, we find in the absence of surface treatment that the piezoelectric properties of ZnO are either effectively lost due to unphysical transformations from the wurtzite to non-piezoelectric d-BCT phases, or also become smaller with decreasing nanowire size. The overall implication of this study is that if enhancement of the piezoelectric properties of ZnO is desired, then continued miniaturization of square * Electronic address: parkhs@bu.edu arXiv:1210.5435v1 [cond-mat.mtrl-sci] 19 Oct 2012 or nearly square cross section ZnO wires to the nanometer scale is not likely to achieve this result.

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Simulation of reconstructions of the polar ZnO(0001)surfaces

Cited by 30 publications

References 31 publications

Hydrogen-induced metallization on the ZnO(0001) surface

Hydrogen-induced metallization on the ZnO(0001) surface

Influence of nonmagnetic Zn substitution on the lattice and magnetoelectric dynamical properties of the multiferroic material CuO

Surface effects on the piezoelectricity of ZnO nanowires

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