Environmental effects of H2O on fracture initiation in silicon: A hybrid electronic-density-functional/molecular-dynamics study

Ogata, Shūji; Shimojo, Fuyuki; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya

doi:10.1063/1.1689004

Cited by 46 publications

(33 citation statements)

References 33 publications

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“…De novo hierarchical simulations also have broad applications in nanoelectronics (Ogata et al 2004). The hybrid QM/MD simulation on the US-Japan Grid described in Section 4 has studied the SIMOX (separation by implantation by oxygen) technique for fabricating high speed and low power-consumption semiconductor devices.…”

Section: Discussionmentioning

confidence: 99%

“…MRMD, F-ReaxFF, and EDC-DFT described above) to enable atomistic simulations that are otherwise too large to solve, while retaining QM accuracy (Broughton et al 1999;Nakano et al 2001;Ogata et al 2001Ogata et al , 2004. The EDC framework achieves this by using less compute-intensive coarse simulation as an embedding field.…”

Section: Adaptive Hierarchical Simulation Frameworkmentioning

confidence: 99%

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De Novo Ultrascale Atomistic Simulations On High-End Parallel Supercomputers

Nakano

Kalia

Nomura

et al. 2008

The International Journal of High Performance Computing Applica

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We present a de novo hierarchical simulation framework for first-principles based predictive simulations of materials and their validation on high-end parallel supercomputers and geographically distributed clusters. In this framework, highend chemically reactive and non-reactive molecular dynamics (MD) simulations explore a wide solution space to discover microscopic mechanisms that govern macroscopic material properties, into which highly accurate quantum mechanical (QM) simulations are embedded to validate the discovered mechanisms and quantify the uncertainty of the solution. The framework includes an embedded divide-andconquer (EDC) algorithmic framework for the design of linear-scaling simulation algorithms with minimal bandwidth complexity and tight error control. The EDC framework also enables adaptive hierarchical simulation with automated model transitioning assisted by graph-based event tracking. A tunable hierarchical cellular decomposition parallelization framework then maps the O(N) EDC algorithms onto petaflops computers, while achieving performance tunability through a hierarchy of parameterized cell data/ computation structures, as well as its implementation using hybrid grid remote procedure call + message passing + threads programming. High-end computing platforms such as IBM BlueGene/L, SGI Altix 3000 and the NSF TeraGrid provide an excellent test grounds for the framework. On these platforms, we have achieved unprecedented scales of quantum-mechanically accurate and well validated, chemically reactive atomistic simulations-1.06 billion-atom fast reactive force-field MD and 11.8 million-atom (1.04 trillion grid points) quantum-mechanical MD in the framework of the EDC density functional theory on adaptive multigridsin addition to 134 billion-atom non-reactive space-time multiresolution MD, with the parallel efficiency as high as 0.998 on 65,536 dual-processor BlueGene/L nodes. We have also achieved an automated execution of hierarchical QM/MD simulation on a grid consisting of 6 supercomputer centers in the US and Japan (in total of 150,000 processor hours), in which the number of processors change dynamically on demand and resources are allocated and migrated dynamically in response to faults. Furthermore, performance portability has been demonstrated on a wide range of platforms such as BlueGene/L, Altix 3000, and AMD Opteron-based Linux clusters.

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Section: Discussionmentioning

confidence: 99%

Section: Adaptive Hierarchical Simulation Frameworkmentioning

confidence: 99%

De Novo Ultrascale Atomistic Simulations On High-End Parallel Supercomputers

Nakano

Kalia

Nomura

et al. 2008

The International Journal of High Performance Computing Applica

Self Cite

View full text Add to dashboard Cite

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“…In the EDC algorithms, spatially localized subproblems are solved in a global embedding field, which is efficiently computed with tree-based algorithms. Examples of the embedding field are 1) the electrostatic field in MD simulations [5], 2) the self-consistent Kohn-Sham potential [6] in the density functional theory (DFT) [7] in quantum-mechanical (QM) simulations [4], and 3) coarser but less computer-intensive models in hierarchical simulations that embed high-accuracy but computerintensive simulations within a coarse simulation only when and where high-fidelity is required [8,9].…”

Section: Scalable Parallel Molecular Dynamics Simulation Algorithmsmentioning

confidence: 99%

Multimillion Atom Reactive Simulations of Nanostructured Energetic Materials

Vashishta¹,

Kalia²,

Nakano³

et al. 2007

Journal of Propulsion and Power

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For large-scale atomistic simulations involving chemical reactions to study nanostructured energetic materials, we have designed linear-scaling molecular dynamics algorithms: 1) first-principles-based fast reactive force field molecular dynamics, and 2) embedded divide-and-conquer density functional theory on adaptive multigrids for quantum-mechanical molecular dynamics. These algorithms have achieved unprecedented scales of quantummechanically accurate and well validated, chemically reactive atomistic simulations [0.56 billion-atom first principles-based fast reactive force field molecular dynamics and 1.4 million-atom (0.12 trillion grid points) embedded divide-and-conquer density functional theory molecular dynamics] in addition to 18.9 billion-atom nonreactive space-time multiresolution molecular dynamics, with parallel efficiency as high as 0.953 on 1920 Itanium2 processors. These algorithms have enabled us to perform reactive molecular dynamics simulations to reveal various atomistic processes during 1) the oxidation of an aluminum nanoparticle, 2) the decomposition and chemisorption of an RDX (1, 3, 5-trinitro-1, 3, 5-triazine) molecule on an aluminum surface, and 3) shock-initiated detonation of energetic nanocomposite material (RDX crystalline matrix embedded with aluminum nanoparticles.

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“…13 This framework consists of (1) a hierarchical division of the physical system into subsystems of increasing quality-of-solution (QoSn) requirements, S 0 ⊃ S 1 ⊃ ... ⊃ S n , and (2) a suite of simulation services, M R (R ) 0, 1, ..., n), of ascending order of accuracy (e.g., EFF < QEq < ReaxFF < QM). We have used the additive hybridization framework to perform (1) QM/EFF-MD simulations of crack initiation in Si in the presence of water molecules, 14 (2) EFF-MD/finite element (FE) simulations of stress distributions at Si/amorphous Si 3 N 4 interfaces, 15 and (3) QM/EFF-MD/FE simulations of oxidation in Si. 13 …”

Section: Hierarchical Simulation Frameworkmentioning

confidence: 99%

Multimillion Atom Simulations of Dynamics of Oxidation of an Aluminum Nanoparticle and Nanoindentation on Ceramics

2006

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We have developed a first-principles-based hierarchical simulation framework, which seamlessly integrates (1) a quantum mechanical description based on the density functional theory (DFT), (2) multilevel molecular dynamics (MD) simulations based on a reactive force field (ReaxFF) that describes chemical reactions and polarization, a nonreactive force field that employs dynamic atomic charges, and an effective force field (EFF), and (3) an atomistically informed continuum model to reach macroscopic length scales. For scalable hierarchical simulations, we have developed parallel linear-scaling algorithms for (1) DFT calculation based on a divide-and-conquer algorithm on adaptive multigrids, (2) chemically reactive MD based on a fast ReaxFF (F-ReaxFF) algorithm, and (3) EFF-MD based on a space-time multiresolution MD (MRMD) algorithm. On 1920 Intel Itanium2 processors, we have demonstrated 1.4 million atom (0.12 trillion grid points) DFT, 0.56 billion atom F-ReaxFF, and 18.9 billion atom MRMD calculations, with parallel efficiency as high as 0.953. Through the use of these algorithms, multimillion atom MD simulations have been performed to study the oxidation of an aluminum nanoparticle. Structural and dynamic correlations in the oxide region are calculated as well as the evolution of charges, surface oxide thickness, diffusivities of atoms, and local stresses. In the microcanonical ensemble, the oxidizing reaction becomes explosive in both molecular and atomic oxygen environments, due to the enormous energy release associated with Al-O bonding. In the canonical ensemble, an amorphous oxide layer of a thickness of ∼40 Å is formed after 466 ps, in good agreement with experiments. Simulations have been performed to study nanoindentation on crystalline, amorphous, and nanocrystalline silicon nitride and silicon carbide. Simulation on nanocrystalline silicon carbide reveals unusual deformation mechanisms in brittle nanophase materials, due to coexistence of brittle grains and soft amorphous-like grain boundary phases. Simulations predict a crossover from intergranular continuous deformation to intragrain discrete deformation at a critical indentation depth.

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Environmental effects of H2O on fracture initiation in silicon: A hybrid electronic-density-functional/molecular-dynamics study

Cited by 46 publications

References 33 publications

De Novo Ultrascale Atomistic Simulations On High-End Parallel Supercomputers

De Novo Ultrascale Atomistic Simulations On High-End Parallel Supercomputers

Multimillion Atom Reactive Simulations of Nanostructured Energetic Materials

Multimillion Atom Simulations of Dynamics of Oxidation of an Aluminum Nanoparticle and Nanoindentation on Ceramics

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