A new parametrization of the widely used Stillinger–Weber potential is proposed for silicon, allowing an improved modelling defects and plasticity-related properties. The performance compared to original version, as well another (Vink et al 2001 J. Non-Cryst. Solids, 282 248), in case several situations: point dislocation core stability, threshold displacement energies, bulk shear, generalized stacking fault energy surfaces, fracture, melting temperature, amorphous structure, crystalline...

Large-scale atomistic calculations, using empirical potentials for modeling semiconductors, have been performed on a stressed system with linear surface defects like steps. Although the elastic limits of systems remain close to theoretical strength, results show that these weaken atomic structure, initializing plastic deformations, in particular dislocations. The character dislocation nucleated can be predicted considering both resolved shear stress related applied orientation and Peierls...

The adsorption and diffusion of single Pb atoms on $\mathrm{Si}(111)\ensuremath{-}(7\ifmmode\times\else\texttimes\fi{}7)$ surfaces have been studied by scanning tunneling microscopy (STM) first-principles density functional calculations. STM experiments at temperatures from 100 to 130 K revealed three regions preferential adsorption, inside each half-unit cell, as well real time events between them. stable sites determined calculations comparing simulated measured images. activation barriers...

We performed molecular dynamics simulations of silicon nanostructures submitted to various stresses and temperatures. For a given stress orientation, transition in the onset plasticity is revealed depending on temperature magnitude. At high low stress, partial dislocation loops are nucleated {111} glide set planes. But at very perfect formed other planes called shuffle. This result confirmed by three different classical potentials suggests that could be controlled nucleation.

The role of a simple surface defect, such as step, for relaxing the stress applied to semiconductor, has been investigated by means large-scale first-principles calculations. Our results indicate that step is privileged site initiating plasticity, with formation and glide $60\ifmmode^\circ\else\textdegree\fi{}$ dislocations both tensile compressive deformations. We have also examined effect termination on plastic mechanisms.

We report an unexpected characteristic of dislocation cores in silicon. Using first-principles calculations, we show that all the stable core configurations for a nondissociated 60\ifmmode^\circ\else\textdegree\fi{} are sessile. The only glissile configuration, previously obtained by nucleation from surfaces, surprisingly corresponds to unstable core. As result, motion is solely driven stress, with no thermal activation. predict this original feature could be relevant situations which large...

Experimentally the silicon nanowires or nanopillars are naturally recovered by a thin oxide layer as soon they exposed to air present an amorphous of when milled focused ion beam (FIB) techniques. Here we investigate role shell on plasticity Si (NWs), thanks molecular dynamics simulations. It is shown that yield strain for nucleation first dislocation decreased NWs with compared pristine nanowires. For circular cross-sections, it thickness has no influence strain. Besides, through...

The effect of various parameters such as temperature or surface state on the very first stages plasticity in semiconductor nanowires has been investigated by molecular dynamics simulations. In particular, role edge and reconstructions analyzed discussed detail. To this end, square with [0 0 1] [1 2 3] axis side surfaces have considered. general, onset appears from NW edges at high stresses. However, when make steps intersection slip plane surface, step can favor dislocation nucleation...

The homogeneous shear of the {111} planes along direction bulk silicon has been investigated using ab initio techniques, to better understand strain properties both shuffle and glide set planes. Similar calculations have done with three empirical potentials, Stillinger–Weber, Tersoff EDIP, in order find one giving best results under large strains. generalized stacking fault energies also calculated these potentials complement this study. It turns out that Stillinger–Weber potential...

Abstract The possible role of surface steps in the nucleation dislocations from a free has been studied by means static atomistic simulation using many-body potential for aluminium. fcc crystal with {100} containing monatomic step lying along (110) dense direction is submitted to an increasing uniaxial stress belonging plane. For sufficiently high applied stress, well below theoretical strength. are nucleated at and glide {111} planes emerging step. effect orientation examined. type...

Defects in free surfaces are expected to be seeds for the nucleation of dislocations, which is likely way nanoscale materials suffer plastic deformation. The results competition between image force attracting dislocation surface and applied strain. In this work, two methods based on molecular dynamics simulations using an embedded atom method (EAM) potential used determine activation energy critical radius formation dislocations from a defect typical fcc metal.

The nucleation of perfect or partial dislocations from a surface-step f.c.c. diamond-like material is frequently observed. In recent paper, it shown how the "stress—stacking-fault energy" plane can be divided into three zones where complete dislocation will not nucleate. compound semiconductors, dissociate α β with mobilities appreciably different. this effect taken account and yields to large modifications in conditions. case GaAs specially examined.

We present first-principles electronic structure calculations combined with scanning tunneling microscopy experiments of the $\mathrm{Si}(111)\ensuremath{-}(\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{3})\ensuremath{-}\mathrm{Pb}$ low-temperature structure. The ab initio have been performed two different atomic configurations. proposed from x-ray data [C. Kumpf, Surf. Sci. 448, L213 (2000)] 1.2 monolayer (ML) coverage is identified as lowest energy one. results calculation are shown to...

Most studies show that materials at the nano-scale have different mechanical properties than in bulk state. Semiconductors like silicon and germanium are brittle state, but when their size is reduced to they appear be ductile. Under tensile loading, we performed molecular dynamics simulations on crystalline nanowires of lengths. We present details obtained mechanisms led ductility brittleness. In case ductility, dislocation nucleation was observed with a signature surface step formation...

Understanding the origin of brittle to ductile transition at low scale in Si requires characterization elementary mechanisms governing crack formation or dislocation nucleation. By molecular dynamics simulations, we have investigated role three surface states silicon nanowires (NWs), fresh cut, reconstructed by annealing 300 K and amorphized, for activation plastic under tensile compressive strains. We show that onset identified as wedge-shaped defect on was only observed fresh-cut NWs...

In a previous static atomistic simulation, it has been shown unambiguously that surface step is privileged site for dislocation nucleation. Before nucleation, an elastic shear, localized in the plane zone with where nucleation will occur, observed. The real forms when this shear reaches, at its maximum, value crystal gets mechanically unstable. part played by stress concentration on localization discussed: although does not involve any glide planes step, produces variation of interplanar...

We have studied the mechanisms of dislocation nucleation from surface defects in silicon submitted to various stresses and temperatures. Molecular dynamics simulations with three classical potentials shown existence two different plastic modes which can be activated surfaces. At high temperatures low dislocations occurs {111} glide set planes, while at large it shuffle planes. The analysis cores kinks shows structures like those well known bulk silicon. This study supports idea that...