Application of a shell model in molecular dynamics simulation to ZnO with zinc-blende cubic structure

Sun, Xiaowei; Chu, Yan-Dong; Song, Ting; Liu, Zhizhuo; Zhang, L.; Wang, X.G.; Liu, Y.X.; Chen, Q.F.

doi:10.1016/j.ssc.2007.01.035

Cited by 16 publications

(11 citation statements)

References 30 publications

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“…The force field developed in this work is based on the interatomic potential derived by Oba et al for ZnO, from which the potential parameters were fitted to the RS cubic structure [36]. These parameters have been demonstrated such that the structural and thermodynamic parameters including equilibrium volume, lattice constant, isothermal bulk modulus, and its pressure derivative at standard condition are in good agreement with available experimental data and the latest theoretical results [33,36-38]. Therefore, the potentials could increase the confidence level of this study.…”

Section: Simulation Modelmentioning

confidence: 80%

Structure-dependent mechanical properties of ultrathin zinc oxide nanowires

Lee

Chang

et al. 2011

Nanoscale Res Lett

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Mechanical properties of ultrathin zinc oxide (ZnO) nanowires of about 0.7-1.1 nm width and in the unbuckled wurtzite (WZ) phase have been carried out by molecular dynamics simulation. As the width of the nanowire decreases, Young's modulus, stress-strain behavior, and yielding stress all increase. In addition, the yielding strength and Young's modulus of Type III are much lower than the other two types, because Type I and II have prominent edges on the cross-section of the nanowire. Due to the flexibility of the Zn-O bond, the phase transformation from an unbuckled WZ phase to a buckled WZ is observed under the tensile process, and this behavior is reversible. Moreover, one- and two-atom-wide chains can be observed before the ZnO nanowires rupture. These results indicate that the ultrathin nanowire possesses very high malleability.

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Section: Simulation Modelmentioning

confidence: 80%

Structure-dependent mechanical properties of ultrathin zinc oxide nanowires

Lee

Chang

et al. 2011

Nanoscale Res Lett

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“…The lattice constant "a" of ZnO (ZB) is about 4.63 Å. 28,29 The d-spacings measured were 2.7 Å -ZnO (111), 2.3 Å -ZnO (220), 1.6 Å -ZnO (220), 1.37 Å -ZnO (311) and 1.31 Å -ZnO (222).…”

Section: Morphology/composition Of the Inner Oxide Layers-mentioning

confidence: 99%

Compact Oxides Formed on Zinc during Exposure to a Single Sea-Water Droplet

Thomas¹,

Cole²,

Birbilis³

2012

J. Electrochem. Soc.

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Compact oxide layers predominantly consisting of zinc oxide naturally grow on zinc upon exposure to a single seawater droplet. SEM and TEM reveal the existence of these oxides beneath the surface, close to the metal surface. EIS demonstrates that these oxides serve as an electrochemical barrier on zinc. The compact oxide immediately above the metal surface is 20-70 nm thick and is undulating in appearance making it difficult to identify crystalline features within. However, the oxide layer above this compact oxide shows a dispersion of a large number of fine-sized voids that cluster in certain areas to form larger voids.Atmospheric corrosion of zinc occurs by contact with deposited aerosols or a thin film of moisture. 1 This results in the formation/precipitation of a number corrosion products (zinc compounds) constituting the zinc patina. 2-7 Droplet experiments have been carried out to understand atmospheric corrosion of zinc by deposited aerosols. [8][9][10][11][12] Electrochemically, droplet tests are significantly different from conventional (bulk) electrochemical tests, as droplets in contact with the metal form micro-electrochemical cells with (i) higher oxygen diffusion to the metal surface, 13,14 ii) low volume of electrolyte contacting the metal, which favors precipitation of zinc corrosion products, and iii) smaller anode-cathode separation, due to a small area of metal exposed and also possibility of cathodic reactions on the corrosion product itself. [15][16][17][18][19] Previous cross-sectional analysis of the Zn patina formed on exposure to a single sea-water droplet using FIB-SEM, revealed that the patina vertically arranges itself as a multi-layered structure. 8,13 The lower layers of the patina especially those in contact with the metal surface were found to become more compact with time.The morphology of the oxide formed on metals, especially passive films, plays an important role in it being an effective barrier against corrosion. Inter-granular sites in passive oxides have been reported to promote passivity breakdown and pitting initiation in metals such as Fe, In those works the passive films were mostly developed by electrochemical polarization in the passive region of the corresponding metal, [22][23][24][25] and not under free-corrosion conditions, which is a more realistic case to test the existence, morphology and impact of the passive layers. Furthermore, the analysis of passive films has been made based on lateral views encompassing only the top surface of these oxides. A sectional view enables visualization/detection of the oxide layers beneath the surface, which may play a more pronounced role in protecting the metal. In bulk electrochemical cells, super-saturated solutions to favor precipitation of corrosion products are rarely achieved, and consequently the role of these corrosion products in protecting the metal is not clearly discernible.In the present study, the oxides formed on zinc after exposure to a 1 μL seawater droplet are analyzed across their cross-section using FIB-SE...

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“…allocating to each shell a fraction of mass of its corresponding core (a shell mass fraction of 10% ensures maximal numerical stability during the simulations) and integrating the motions in the same way as that of the core, by integration of classical equations of motion with a time step of 0.1 fs. Such a method has been applied to various ionic materials and has been proved successful and computationally efficient [33][34][35][36]. As built, the two simulation cells can also be used to investigate the dislocation behaviour under σ xy or σ xz stress loading.…”

Section: Methodsmentioning

confidence: 99%

On the glide of [100] dislocation and the origin of ‘pencil glide’ in Mg₂SiO₄olivine

Mahendran

Carrez

2019

Philosophical Magazine

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Olivine with chemical composition (Mg,Fe) 2 SiO 4 is a silicate which is supposed to strongly constrain the flow of the Earth's upper mantle under thermal convection. Its mechanical properties are thus of primary importance. Slip systems in olivine involve two types of dislocations with [100] and [001] Burgers vectors. In this study, we report atomistic modelling of screw dislocations with [100] Burgers vector and their intrinsic properties. We show that the [100] screw dislocation core exhibits several configurations corresponding to spreading in different planes and different relative stabilities. At low pressure, we identify a clear tendency for core spreading in (010). At higher pressure, relevant for the Earth's mantle, we show that pressure promotes a change in core configuration with spreading into equivalent {021} planes. Based on the systematic investigation of the minimum energy path between the different configurations, we show that the variability of core structures allows complex glide paths which has been described at the macroscopic level as 'pencil glide'. Our results suggest that the pencil glide is more efficient at high pressure.

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Application of a shell model in molecular dynamics simulation to ZnO with zinc-blende cubic structure

Cited by 16 publications

References 30 publications

Structure-dependent mechanical properties of ultrathin zinc oxide nanowires

Structure-dependent mechanical properties of ultrathin zinc oxide nanowires

Compact Oxides Formed on Zinc during Exposure to a Single Sea-Water Droplet

On the glide of [100] dislocation and the origin of ‘pencil glide’ in Mg₂SiO₄olivine

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Application of a shell model in molecular dynamics simulation to ZnO with zinc-blende cubic structure

Cited by 16 publications

References 30 publications

Structure-dependent mechanical properties of ultrathin zinc oxide nanowires

Structure-dependent mechanical properties of ultrathin zinc oxide nanowires

Compact Oxides Formed on Zinc during Exposure to a Single Sea-Water Droplet

On the glide of [100] dislocation and the origin of ‘pencil glide’ in Mg2SiO4olivine

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On the glide of [100] dislocation and the origin of ‘pencil glide’ in Mg₂SiO₄olivine