Undissociated screw dislocations in silicon: Calculations of core structure and energy

Pizzagalli, Laurent; Beauchamp, P.; Rabier, J.

doi:10.1080/0141861031000071999

Cited by 53 publications

(70 citation statements)

References 29 publications

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“…On the basis of geometrical arguments, it has been suggested that this mixed shuffle-glide configuration is a saddle point, and therefore, is not stable [28]. This has been confirmed for Si by first principles calculations [12]. Therefore, in this work, the B configuration is obtained by constraining the two atoms closest to the dislocation line to remain at the same distance along [101].…”

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confidence: 98%

“…So far, theoretical studies have shown that the non-dissociated screw belongs to the 'shuffle' set, though there has been a controversy about the most stable structure [11,12]. Other covalent materials with zinc-blende structure are expected to behave like silicon, at least at high temperature.…”

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confidence: 99%

“…Periodic boundary conditions are applied to recover the quadrupolar arrangement [3]. After relaxation, quantities attached to a single dislocation are obtained by removing contributions from dislocation interactions, determined from anisotropic elasticity theory [12]. Density functional theory calculations have been performed with the ABINIT code [26].…”

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Stability of undissociated screw dislocations in zinc-blende covalent materials from first-principle simulations

2005

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Abstract. -The properties of perfect screw dislocations have been investigated for several zinc-blende materials such as diamond, Si, β-SiC, Ge and GaAs, by performing first principles calculations. For almost all elements, a core configuration belonging to shuffle set planes is favored, in agreement with low temperature experiments. Only for diamond, a glide configuration has the lowest defect energy, thanks to an sp 2 hybridization in the core.Several technologically interesting covalent materials are semiconductors or insulators with a zinc-blende crystalline structure. The most famous is silicon, extensively used in electronic devices. It is usually considered as a model for other materials with the same structure, and most of its properties are well known, thanks to an impressive number of dedicated studies. For instance, the plasticity of silicon has been largely investigated both experimentally and theoretically. At high temperature, silicon is ductile, and dislocations are dissociated into Shockley partials; since the dislocations are frequently aligned along the 110 dense directions, they mostly appear as 30• and 90• partials and slip in the so-called 'glide' set of {111} planes (Fig. 1) [1]. Calculations have allowed to determine the core structure of partials [2][3][4], although the most stable configuration of the 90• is still not known with certainty [5][6][7][8]. At low temperature, in the brittle regime, surface scratch tests and confining pressure experiments have recently revealed the presence of undissociated dislocations, with screw, 60• , 30• and 41• orientations [9,10], so that very little investigation of these perfect dislocations recently have been reported. So far, theoretical studies have shown that the non-dissociated screw belongs to the 'shuffle' set, though there has been a controversy about the most stable structure [11,12]. Other covalent materials with zinc-blende structure are expected to behave like silicon, at least at high temperature. Partial dislocations have been theoretically characterized for β-SiC (cubic 3C-SiC) [13][14][15], diamond [16][17][18], Ge [7,8,19], GaAs [20,21], and others [22,23]. However, it is not clear whether the results obtained at low temperature for silicon remained valid for those materials, and little is known on that subject. Experiments have shown that low temperature deformation of GaAs yields undissociated screw dislocations [24], like in silicon, and recent calculations by Blumenau et al focussed on perfect screw in diamond [15].

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Stability of undissociated screw dislocations in zinc-blende covalent materials from first-principle simulations

2005

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“…For example, if the considered dislocations are ideally straight and infinite, the core structure may be investigated with few hundreds of atoms. Precise electronic and atomic structure calculations can then be performed using ab initio methods [1,2,3,4,5]. Still, investigating the formation, mobility or interaction of dislocations requires a large system with a few thousands of atoms [6], preventing the use of such methods.…”

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Comparison between classical potentials andab initiomethods for silicon under large shear

Godet

Pizzagalli

Brochard

et al. 2003

J. Phys.: Condens. Matter

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Abstract.The homogeneous shear of the {111} planes along the < 110 > direction of bulk silicon has been investigated using ab initio techniques, to better understand the strain properties of both shuffle and glide set planes. Similar calculations have been done with three empirical potentials, Stillinger-Weber, Tersoff and EDIP, in order to find the one giving the best results under large shear strains. The generalized stacking fault energies have also been calculated with these potentials for complementing this study. It turns out that the Stillinger-Weber potential better reproduces the ab initio results, for the smoothness and the amplitude of the energy variation as well as the localisation of shear in the shuffle set.

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“…First, in this work we have favored a shuffle core for the screw dislocation [25], although it has been shown that a glide core is energetically more stable [26,27]. Our choice has been motivated by the fact that the glide core is necessarily reconstructed along the dislocation line, yielding a structure close to reconstructed partial dislocation cores.…”

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Dislocation motion in silicon: the shuffle-glide controversy revisited

Pizzagalli

Beauchamp

2008

Philosophical Magazine Letters

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Undissociated screw dislocations in silicon: Calculations of core structure and energy

Cited by 53 publications

References 29 publications

Stability of undissociated screw dislocations in zinc-blende covalent materials from first-principle simulations

Stability of undissociated screw dislocations in zinc-blende covalent materials from first-principle simulations

Comparison between classical potentials andab initiomethods for silicon under large shear

Dislocation motion in silicon: the shuffle-glide controversy revisited

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