Ab initio Calculations for SrTiO3 (100) Surface Structure

Heifets, E.; Eglitis, R. I.; Kotomin, Eugene A.; Börstel, G.

doi:10.1063/1.1499578

Cited by 5 publications

(6 citation statements)

References 19 publications

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“…Finally, we note that there are other potential mechanisms for compensating the macroscopic dipole, such as redistributing the charges on the existing ions and charge transfer effects that cannot be captured with the present methodology. In particular, a considerable increase of near-surface covalency was shown in DFT calculations of SrTiO 3 (100) surface and polar (110) surface. , However, in other cases, such filling of electronic states at the surface tend to be unfavorable, suggesting that the approach used here is energetically competitive with other approaches…”

Section: Methodsmentioning

confidence: 86%

Atomic-Scale Structure and Stability of the Low-Index Surfaces of Pyrochlore Oxides

2016

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The multifunctional properties of complex ternary oxides such as pyrochlores are often influenced by surface structure. Optimizing the surface-driven attributes of these materials necessitates a detailed understanding of the structure and chemical composition of those surfaces. Here we report atomistic simulations elucidating the diverse atomic-scale structures of a set of low-index surfaces [(100), ( 110), (111), and ( 112)] in pyrochlore compounds as a function of both A and B cation chemistry. In pyrochlores, the low-index facets are all dipolar, requiring the introduction of surface defects to eliminate the surface dipole. We find that, due to the corresponding higher coordination of the surface cations, the (110) facet is the most energetically stable in all of the compounds considered, an interesting contrast to fluorite, in which the (111) surface is most stable. We also reveal a correlation between the surface energy and the energy to disorder the pyrochlore as a function of B cation chemistry, implying a similar physical origin for the two phenomena. Further, we find that surface rumpling is common across all pyrochlore compounds. An even more interesting feature emerging at these surfaces is the formation of extended structural defects such as steps and trenches, which are found to be stable after high-temperature annealing. As the formation of these features is a consequence of surface defects introduced to eliminate the surface dipole, we propose that the superior surface properties of materials of pyrochlores are due to these extended structural features, which are a direct consequence of the inherent dipole at the surfaces.

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Section: Methodsmentioning

confidence: 86%

Atomic-Scale Structure and Stability of the Low-Index Surfaces of Pyrochlore Oxides

2016

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“…Surface energy is a measure of the energy necessary for the destruction of chemical bonds between atoms when creating a crystal surface. It can also be thought of as the extra energy of the surface relative to the crystal interior . It can therefore be calculated using Equation :

γ_{surf} = \frac{1}{2 S} ((), E_{surf} - E_{bulk}),

where S is the area of the AlN surface, γ surf is the interfacial energy, and E surf and E bulk are the free energies of the surface model and that of the bulk model, respectively.…”

Section: Resultsmentioning

confidence: 99%

First principle calculations study of AlN surface terminal structure evolution under different conditions

Sun

Ren

Tan

2019

Surface & Interface Analysis

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The surface structure and properties of aluminum nitride (AlN) play an important role in many applications. Using the first principle calculations method, we analyzed the surface terminal structure of AlN and its evolution under different conditions by determining the surface energy, adsorption energy, and evaporation energy of the Al and N terminals on the AlN(0001) surface. Our results show that the reason why the N terminal is less stable than the Al terminal is not only because of its high surface energy but also because its adsorption performance is extremely sensitive to the adsorption position. The surface N atoms combine to form N2 molecules that escape during the evaporation process at high temperature. After surface N atoms escape, the AlN surface structure reconstitutes to form a 3×3−R30° hexagonal closest packing (HCP)–like structure, and the energy barrier for the reconstructing process is 3.2 eV. This shows that the structure and form of the AlN(0001) terminals depend on the environmental conditions.

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“…However, no matter which plane was exposed, the lowest energy principle would be followed. Take the STO as an example, It can be deduced from the literature that the {100}, {110}, and {111} planes had surface energy close to each other, which implied that each of them may be exposed according to the preferred orientation of the film. This accounted for the STO films with the (110) and (100) preferred orientations exposed different facets of {110}, {111}, and {100}.…”

Section: Resultsmentioning

confidence: 99%

Preparation of (110)‐oriented SrTiO₃ film on quartz glass by laser chemical vapor deposition

Zhao

Zhang

et al. 2018

J Am Ceram Soc

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SrTiO3 (STO) film was prepared on quartz glass by laser chemical vapor deposition at a deposition temperature (Tdep) ranged from 760 to 1104 K. Effect of the Tdep on the orientation, crystallinity, texture, and microstructure of the STO film was investigated. As the Tdep was increased, the preferred orientation of the STO film tended to be (110)‐orientated with corresponding texture coefficient (TC) on the (110) reflection enhanced from 2.3 to 6; meanwhile, the full width at half maximum of the ω‐scan on the (110) reflection decreased from 0.85° to 0.59°. The (110)‐oriented grains were in wedge shape about 60 × 150 nm in size, which tended to be flat at an elevated Tdep of 1104 K.

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Ab initio Calculations for SrTiO3 (100) Surface Structure

Cited by 5 publications

References 19 publications

Atomic-Scale Structure and Stability of the Low-Index Surfaces of Pyrochlore Oxides

Atomic-Scale Structure and Stability of the Low-Index Surfaces of Pyrochlore Oxides

First principle calculations study of AlN surface terminal structure evolution under different conditions

Preparation of (110)‐oriented SrTiO₃ film on quartz glass by laser chemical vapor deposition

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Ab initio Calculations for SrTiO3 (100) Surface Structure

Cited by 5 publications

References 19 publications

Atomic-Scale Structure and Stability of the Low-Index Surfaces of Pyrochlore Oxides

Atomic-Scale Structure and Stability of the Low-Index Surfaces of Pyrochlore Oxides

First principle calculations study of AlN surface terminal structure evolution under different conditions

Preparation of (110)‐oriented SrTiO3 film on quartz glass by laser chemical vapor deposition

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Product

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Preparation of (110)‐oriented SrTiO₃ film on quartz glass by laser chemical vapor deposition