Electric field tuning of oxygen stoichiometry at oxide surfaces: molecular dynamics simulations studies of zirconia

Sankaranarayanan, Subramanian K. R. S.; Kaxiras, Efthimios; Ramanathan, Shriram

doi:10.1039/b913154j

Cited by 29 publications

(27 citation statements)

References 43 publications

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“…= 6.25!MV/cm in our calculations here. This is similar to values used by Sankaranarayan et al's prior MD studies on oxidation of Zr and Al [25,26,27]. Using an estimated charge (q) of 4.65 ± 0.18!…”

Section: Case Study: Oxidation Of Ta (110) Surfacesupporting

confidence: 81%

“…5 b, e) reach a limiting value of ~0.7-0.9 nm. Similar self-limiting thicknesses have been obtained for the natural oxidation of Zr both from MD and experiments [25,27,55]. In addition, Mathieu et al [56] reported natural oxide film thicknesses ranging from 0.…”

Section: Case Study: Oxidation Of Ta (110) Surfacesupporting

confidence: 71%

“…The optimized parameters are used to investigate the initial stages of oxidation of metallic Ta by employing a similar approach used by Sankaranarayanan et al [25,26,27]. The LAMMPS MD package [40] is used to perform all the simulations in this work.…”

Section: Oxidation Simulation Set-upmentioning

confidence: 99%

“…To model such a scenario, one requires a potential model such as charge transfer ionic potential (CTIP) that seamlessly allows for switching between an environment dominated by ionic interactions in the oxide and metallic interactions in the metal region. This formalism has been successfully used in the past to investigate oxidation of several metal and alloy surfaces and nanoparticles [25,26,27,28]. To determine the force-field parameters for complex functional forms like CTIP, we require a systematic approach that can enable efficient sampling of most of the available parameter space.…”

Section: Introductionmentioning

confidence: 99%

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Evolutionary Optimization of a Charge Transfer Ionic Potential Model for Ta/Ta-Oxide Heterointerfaces

et al. 2017

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Heterostructures of tantalum and its oxide are of tremendous technological interest for a myriad of technological applications, including electronics, thermal management, catalysis and biochemistry. In particular, local oxygen stoichiometry variation in TaO x memristors comprising of thermodynamically stable metallic (Ta) and insulating oxide (Ta 2 O 5 ) have been shown to result in fast switching on the subnanosecond timescale over a billion cycles. This rapid switching opens up the potential for advanced functional platforms such as stateful logic operations and neuromorphic computation. Despite its broad importance, an atomistic scale understanding of oxygen stoichiometry variation across Ta/TaO x heterointerfaces, such as during early stages of oxidation and oxide growth, is not well understood. This is mainly due to the lack of a unified interatomic potential model for tantalum oxides that can accurately describe metallic (Ta), ionic (TaO x ) as well as mixed (Ta/TaO x interfaces) bonding environments simultaneously. To address this challenge, we introduce a Charge Transfer Ionic Potential (CTIP) model for Ta/Ta-oxide system by training against lattice parameters, cohesive energies, equations of state (EOS), elastic properties, and surface energies of the various experimentally observed Ta 2 O 5 polymorphs (hexagonal, orthorhombic and monoclinic) obtained from density functional theory (DFT) calculations.The best CTIP parameters are determined by employing a global optimization scheme driven by genetic algorithms followed by local Simplex optimization. Our newly developed CTIP potential accurately

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Section: Case Study: Oxidation Of Ta (110) Surfacesupporting

confidence: 81%

Section: Case Study: Oxidation Of Ta (110) Surfacesupporting

confidence: 71%

Section: Oxidation Simulation Set-upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evolutionary Optimization of a Charge Transfer Ionic Potential Model for Ta/Ta-Oxide Heterointerfaces

et al. 2017

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“…It has been shown that a significant impact on the oxidation kinetics can be achieved by either directly applying an external electric field [3][4][5][6][7][8][9][10] or electron bombardment of the oxide surface [11][12][13]. We demonstrate here that the actual value of the self-generated electrostatic potential (designated as the kinetic potential [14]) can deviate from the Mott potential and is tunable by varying the oxygen pressure during oxidation which provides control of the limiting thickness of the oxide film.…”

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confidence: 99%

Tuning the Limiting Thickness of a Thin Oxide Layer on Al(111) with Oxygen Gas Pressure

et al. 2011

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We report an x-ray photoelectron spectroscopy study of the oxidation of Al(111) surfaces at room temperature, which reveals that the limiting thickness of an aluminum oxide film can be tuned by using oxygen pressure. This behavior is attributed to a strong dependence of the kinetic potential on the oxygen gas pressure. The coverage of oxygen anions on the surface of the oxide film depends on the gas pressure leading to a pressure dependence of the kinetic potential. Our results indicate that a significantly large oxygen pressure (>1 Torr) is required to develop the saturated surface coverage of oxygen ions, which results in the maximum kinetic potential and therefore the saturated limiting thickness of the oxide film.

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Stainless steel surface wettability control via laser ablation in external electric field

et al. 2016

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Electric field tuning of oxygen stoichiometry at oxide surfaces: molecular dynamics simulations studies of zirconia

Cited by 29 publications

References 43 publications

Evolutionary Optimization of a Charge Transfer Ionic Potential Model for Ta/Ta-Oxide Heterointerfaces

Evolutionary Optimization of a Charge Transfer Ionic Potential Model for Ta/Ta-Oxide Heterointerfaces

Tuning the Limiting Thickness of a Thin Oxide Layer on Al(111) with Oxygen Gas Pressure

Stainless steel surface wettability control via laser ablation in external electric field

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