Recent Developments in IMD: Interactions for Covalent and Metallic Systems

Bitzek, Erik; Gähler, Franz; Hahn, Jutta; Kohler, Christopher C.; Krdzalic, Galib; Roth, Johannes; Rudhart, Christoph; Schaaf, Gunther; Stadler, Jörg; Trebin, Hans‐Rainer

doi:10.1007/978-3-642-56548-9_3

Cited by 8 publications

(7 citation statements)

References 10 publications

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“…The applied forces were then instantaneously removed, and the wires were relaxed for 400 ps at 300 K. All simulations were performed using the MD software package IMD. 88 The defect structures were analyzed using common neighbor analysis, 89 coordination number, and the dislocation extraction algorithm 90 as implemented in the atomistic visualization tool OVITO. 91 …”

Section: Methodsmentioning

confidence: 99%

“…For more details of the bending simulation method, see Nöhring et al Simulations were performed at 300 K with the Nosé–Hoover thermostat, and applied forces were increased by F ̇ bend = 300 N/s. The applied forces were then instantaneously removed, and the wires were relaxed for 400 ps at 300 K. All simulations were performed using the MD software package IMD . The defect structures were analyzed using common neighbor analysis, coordination number, and the dislocation extraction algorithm as implemented in the atomistic visualization tool OVITO …”

Section: Methodsmentioning

confidence: 99%

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Microscopic Deformation Modes and Impact of Network Anisotropy on the Mechanical and Electrical Performance of Five-fold Twinned Silver Nanowire Electrodes

et al. 2020

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Silver nanowire (AgNW) networks show excellent optical, electrical, and mechanical properties, which make them ideal candidates for transparent electrodes in flexible and stretchable devices. Various coating strategies and testing setups have been developed to further improve their stretchability and to evaluate their performance. Still, a comprehensive microscopic understanding of the relationship between mechanical and electrical failure is missing. In this work, the fundamental deformation modes of five-fold twinned AgNWs in anisotropic networks are studied by large-scale SEM straining tests that are directly correlated with corresponding changes in the resistance. A pronounced effect of the network anisotropy on the electrical performance is observed, which manifests itself in a one order of magnitude lower increase in resistance for networks strained perpendicular to the preferred wire orientation. Using a scale-bridging microscopy approach spanning from NW networks to single NWs to atomic-scale defects, we were able to identify three fundamental deformation modes of NWs, which together can explain this behavior: (i) correlated tensile fracture of NWs, (ii) kink formation due to compression of NWs in transverse direction, and (iii) NW bending caused by the interaction of NWs in the strained network. A key observation is the extreme deformability of AgNWs in compression. Considering HRTEM and MD simulations, this behavior can be attributed to specific defect processes in the five-fold twinned NW structure leading to the formation of NW kinks with grain boundaries combined with V-shaped surface reconstructions, both counteracting NW fracture. The detailed insights from this microscopic study can further improve fabrication and design strategies for transparent NW network electrodes.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Microscopic Deformation Modes and Impact of Network Anisotropy on the Mechanical and Electrical Performance of Five-fold Twinned Silver Nanowire Electrodes

et al. 2020

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“…In IMD, scalar optimizations similar to those we describe here are implemented [12], [11]; however, no sort of vectorization is included. Our work is in part based on previous efforts to port MD simulations, and LAMMPS in particular, to the Xeon Phi [18]; specifically, we use the same data and computation management scheme.…”

Section: Related Workmentioning

confidence: 99%

The Vectorization of the Tersoff Multi-body Potential: An Exercise in Performance Portability

Höhnerbach

Ismail

Bientinesi

2016

SC16: International Conference for High Performance Computing, Networking, Storage and Analysis

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Molecular dynamics simulations, an indispensable research tool in computational chemistry and materials science, consume a significant portion of the supercomputing cycles around the world. We focus on multi-body potentials and aim at achieving performance portability. Compared with well-studied pair potentials, multibody potentials deliver increased simulation accuracy but are too complex for effective compiler optimization. Because of this, achieving cross-platform performance remains an open question. By abstracting from target architecture and computing precision, we develop a vectorization scheme applicable to both CPUs and accelerators. We present results for the Tersoff potential within the molecular dynamics code LAMMPS on several architectures, demonstrating efficiency gains not only for computational kernels, but also for large-scale simulations. On a cluster of Intel Xeon Phi's, our optimized solver is between 3 and 5 times faster than the pure MPI reference.

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“…For Nb, Mo and W, the additional potential parameterizations by Fellinger et al [53], Ackland et al [54,55], Smirnova et al [56], and Wang et al [57] were used as well. All EAM potentials used in our study are listed in Table II. In case of EAM potentials, energy minimization is performed using the software package IMD [58,59] with the FIRE relaxator [60] until the force-norm F is below 10 −8 eV/Å.…”

Section: B Embedded Atom Methods Potentialsmentioning

confidence: 99%

“…In case of EAM potentials, energy minimization is performed using the software package IMD [58,59] with the FIRE relaxator [60] until the force-norm F is below 10 −8 eV/ Å.…”

Section: B Embedded Atom Methods Potentialsmentioning

confidence: 99%

{110} planar faults in strained bcc metals: Origins and implications of a commonly observed artifact of classical potentials

Möller

Mrovec

Bleskov

et al. 2018

Phys. Rev. Materials

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Large-scale atomistic simulations with classical potentials can provide valuable insights into microscopic deformation mechanisms and defect-defect interactions in materials. Unfortunately, these assets often come with the uncertainty of whether the observed mechanisms are based on realistic physical phenomena or whether they are artifacts of the employed material models. One such example is the often reported occurrence of stable planar faults (PFs) in body-centered cubic (bcc) metals subjected to high strains, e.g., at crack tips or in strained nano-objects. In this paper, we study the strain dependence of the generalized stacking fault energy (GSFE) of {1 1 0} planes in various bcc metals with material models of increasing sophistication, i.e., (modified) embedded atom method, angular-dependent, Tersoff, and bond-order potentials as well as density functional theory. We show that under applied tensile strains the GSFE curves of many classical potentials exhibit a local minimum which gives rise to the formation of stable PFs. These PFs do not appear when more sophisticated material models are used and have thus to be regarded as artifacts of the potentials. We demonstrate that the local GSFE minimum is not formed for reasons of symmetry and we recommend including the determination of the strain-dependent (1 1 0) GSFE as a benchmark for newly developed potentials.

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Recent Developments in IMD: Interactions for Covalent and Metallic Systems

Cited by 8 publications

References 10 publications

Microscopic Deformation Modes and Impact of Network Anisotropy on the Mechanical and Electrical Performance of Five-fold Twinned Silver Nanowire Electrodes

Microscopic Deformation Modes and Impact of Network Anisotropy on the Mechanical and Electrical Performance of Five-fold Twinned Silver Nanowire Electrodes

The Vectorization of the Tersoff Multi-body Potential: An Exercise in Performance Portability

{110} planar faults in strained bcc metals: Origins and implications of a commonly observed artifact of classical potentials

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