Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 12: Computational Materials Modelling - Mechanical Properties

MM 12.7: Vortrag

Montag, 11. März 2013, 17:15–17:30, H24

Modeling of pressure-induced phase transformation in Si using a two phases strategy — Sebastien Groh, •Michael Budnitsky, and Meinhard Kuna — TU Bergakademie Freiberg, Freiberg, Germany

We have carried out constant pressure molecular dynamics simulation with a Tersoff interatomic potential to study the pressure-induced phase transformation in Si using a two-phases model. The simulations successfully reproduced the diamond-cubic to β-Sn structural transformation under hydrostatic pressure. The pressure level at which the transformation occurred is in agreement with both experimental data and thermodynamics considerations. Moreover, the mechanism of phase transformation by inhomogeneous shear deformation was revealed by the calculations. Furthermore, as the β-Sn cannot transform back to diamond-cubic structure, it was observed in the simulation that the two-phases model transformed to a diamond- cubic and an amorphous Si for pressure lower than the transition pressure. Although such a transformation from β-Sn to amorphous Si was already observed by simulation of nanoindentation of Si using MD, it is the first that time this transformation is reported under hydrostatic loading conditions using molecular dynamics simulations.