Crystallization of amorphous silicon induced by mechanical shear deformations

TL;DR

This study uses molecular dynamics simulations to explore how mechanical shear deformations can induce crystallization in amorphous silicon, revealing a temperature-dependent transition from disorder to crystalline structure.

Contribution

It demonstrates that shear-induced crystallization in amorphous silicon occurs at high temperatures, highlighting the role of shear rate and temperature in phase transformation.

Findings

Shear deformations increase disorder at low temperature and shear rate.

High temperature shear induces crystallization in amorphous silicon.

Crystallization extent correlates with potential energy difference and defect fraction.

Abstract

We have investigated the response of amorphous silicon (a-Si), in particular crystallization, to external mechanical shear deformations using classical molecular dynamics (MD) simulations and the empirical Environment Dependent Inter-atomic Potential (EDIP) [Phys. Rev. B 56, 8542 (1997)]. In agreement with previous results we find that, at low shear velocity and low temperature, shear deformations increase disorder and defect density. At high temperatures, however, the deformations are found to induce crystallization, demonstrating a dynamical transition associated with both shear rate and temperature. The properties of a-Si under shear deformations and the extent at which the system crystallizes are analyzed in terms of the potential energy difference (PED) between the sheared and non-sheared material, as well as the fraction of defects and the number of particles that possess a crystalline environment.