Molecular dynamics simulations of α-alumina and γ-alumina surfaces

Błoński, Sławomir; Garofalini, Stephen H.

doi:10.1016/0039-6028(93)90202-u

Cited by 252 publications

(165 citation statements)

References 16 publications

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“…The only values reported in the literature for the surface energies of the ͕111͖, ͕110͖, and ͕100͖ crystallographic faces of ␥-Al 2 O 3 are theoretical ones obtained from moleculardynamics simulations pertaining to 300 K of the corresponding relaxed and unrelaxed surfaces of ␥-Al 2 O 3 in contact with vacuum ͑i.e., ␥-͗␥-Al 2 O 3 ͘-vac ͒. 12 ͕110͖:…”

Section: Thermodynamics Of Amorphous and Crystalline Aluminum-oximentioning

confidence: 99%

Thermodynamic stability of amorphous oxide films on metals: Application to aluminum oxide films on aluminum substrates

et al. 2000

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It has been shown on a thermodynamic basis that an amorphous structure for an oxide film on its metal substrate can be more stable than the crystalline structure. The thermodynamic stability of a thin amorphous metal-oxide film on top of its single-crystal metal substrate has been modeled as a function of growth temperature, oxide-film thickness, and crystallographic orientation of the metal substrate. To this end, expressions have been derived for the estimation of the energies of the metal-substrate amorphous-oxide film interface and the metal-substrate crystalline-oxide film interface as a function of growth temperature, and crystallographic orientation of the substrate ͑including the effect of strain due to the lattice mismatch͒. It follows that, up to a certain critical thickness of the amorphous oxide film, the higher bulk Gibbs free energy of the amorphous oxide film, as compared to the corresponding crystalline oxide film, can be compensated for by the lower sum of the surface and interfacial energies. The predicted occurrence of an amorphous aluminum-oxide film on various crystallographic faces of aluminum agrees well with previous transmission electron microscopy observations.

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Section: Thermodynamics Of Amorphous and Crystalline Aluminum-oximentioning

confidence: 99%

Thermodynamic stability of amorphous oxide films on metals: Application to aluminum oxide films on aluminum substrates

et al. 2000

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“…This is also in line with what computational studies have showed. 11,12 However, the amount ͑and in some cases also the direction͒ of the relaxations of the outermost layers show a spread in values both in experimental investigations and early theoretical studies. 8,10,13,14 More recent first-principles calculations have revealed that the origin of the experimental inconsistencies could be hydrogen on the surface.…”

Section: Introductionmentioning

confidence: 99%

Ab initiostudies of Al, O, andO2adsorption onα−Al2O3
Wallin
¹
,
Andersson
²
,
Münger
³

et al. 2006
Phys. Rev. B
44
5
39
0
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The interactions of Al, O, and O 2 with different ␣-Al 2 O 3 ͑0001͒ surfaces have been studied using ab initio density functional theory methods. All three surface terminations obtainable by cleaving the bulk structure ͓single Al-layer ͑AlO͒, double Al-layer ͑AlAl͒, and O terminations͔ have been considered, as well as a completely hydrogenated O-terminated surface. Adsorbed Al shows strong ioniclike interaction with the AlOand O-terminated surfaces, and several metastable adsorption sites are identified on the O-terminated surface. On the completely hydrogenated surface, however, Al adsorption in the bulk position is found to be unstable or very weak for the studied configurations of surface H atoms. Atomic O is found to interact strongly with the AlAl-terminated surface, where also O 2 dissociative adsorption without any appreciable barrier is observed. In contrast, O adsorption on the AlO-terminated surface is metastable relative to molecular O 2 . On the O-terminated surface, we find the creation of O surface vacancies to be plausible, especially upon exposure to atomic O at elevated temperatures. The results are mainly discussed in the context of alumina thin film growth and provide insight into phenomena related to, e.g., preferred adsorption sites and effects of hydrogen on the growth.

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“…Canonical ensembles at 330 K ͑slightly above room temperature due to irradiation from plasma͒ were used to simulate Al bombardment of alumina slabs ͑vacuum thickness 10 16,34 Structural description of ␣-and ␥-Al 2 O 3 bulk/surfaces was adopted from literature. [35][36][37] The MD time step was 1.0 fs and the total MD simulation time was 400 fs, namely 100 fs for surface relaxations and 300 fs after bombardment events. These MD time scales are large enough to model fast irradiation-induced processes, according to a previous study.…”

mentioning

confidence: 99%

“…Furthermore, the mean square displacement for ␣-Al 2 O 3 ͑0001͒ bombarded with 3.5 eV Al is 0.45 Å 2 . Since ␣-Al 2 O 3 ͑0001͒ is O-terminated during vapor phase condensation in the presence of O 2 , unlike ␥-Al 2 O 3 ͑001͒ which is known to exhibit a mixed termination, 37 the bombardment of O-surface sites with and without underlying Al can be studied. However, all irradiation studies on Al 2 O 3 ͑0001͒ were performed for O without underlying Al so that possible irradiation damage is maximized.…”

mentioning

confidence: 99%

Ab initio molecular dynamics of Al irradiation-induced processes during Al2O3 growth

Mušić

Nahif

Sarakinos

et al. 2011

Applied Physics Letters

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Al bombardment induced structural changes in α-Al2O3 (R-3c) and γ-Al2O3 (Fd-3m) were studied using ab initio molecular dynamics. Diffusion and irradiation damage occur for both polymorphs in the kinetic energy range from 3.5 to 40 eV. However, for γ-Al2O3(001) subplantation of impinging Al causes significantly larger irradiation damage and hence larger mobility as compared to α-Al2O3. Consequently, fast diffusion along γ-Al2O3(001) gives rise to preferential α-Al2O3(0001) growth, which is consistent with published structure evolution experiments.

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Molecular dynamics simulations of α-alumina and γ-alumina surfaces

Cited by 252 publications

References 16 publications

Thermodynamic stability of amorphous oxide films on metals: Application to aluminum oxide films on aluminum substrates

Thermodynamic stability of amorphous oxide films on metals: Application to aluminum oxide films on aluminum substrates

Ab initiostudies of Al, O, andO2adsorption onα−Al2O3
Wallin
¹
,
Andersson
²
,
Münger
³

et al. 2006
Phys. Rev. B
44
5
39
0
View full text Add to dashboard Cite

Ab initio molecular dynamics of Al irradiation-induced processes during Al2O3 growth

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Molecular dynamics simulations of α-alumina and γ-alumina surfaces

Cited by 252 publications

References 16 publications

Thermodynamic stability of amorphous oxide films on metals: Application to aluminum oxide films on aluminum substrates

Thermodynamic stability of amorphous oxide films on metals: Application to aluminum oxide films on aluminum substrates

Ab initiostudies of Al, O, andO2adsorption onα−Al2O3Wallin1, Andersson2, Münger3 et al. 2006Phys. Rev. B445390View full textAdd to dashboardCite

Ab initio molecular dynamics of Al irradiation-induced processes during Al2O3 growth

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Ab initiostudies of Al, O, andO2adsorption onα−Al2O3
Wallin
¹
,
Andersson
²
,
Münger
³

et al. 2006
Phys. Rev. B
44
5
39
0
View full text Add to dashboard Cite