Pressure effect on the icosahedral order of Pd50Si50 alloy: A molecular dynamics study

Abstract

Molecular dynamics (MD) simulation based on Quantum Embedded Atom Method (EAM) has been used to determine the effect of pressure on icosahedral (icos) order of Pd50Si50 alloy system at nano-scale under different pressures. The icosahedral local order was analysed with ideal icosahedral and defective icosahedral clusters in the system. The Honeycutt-Andersen (HA) and cluster-type index (CTIM) methods have been proposed to describe these clusters. The bond orientational order (BOO) parameters have been calculated to detect icos order in the system. On the other hand, the radial distribution function (RDF) is examined to determine structural development of system. The results of these three analysis method reveal that the increase of pressure leads to the formation of 1551 bonded pairs representing ideal icos, (12 0 12 0) ideal icos polyhedrons. The values of Ql and Wˆl order parameters are close to ideal icos value of -0.169754 with pressure value of 10 GPa. But, the icos order structure transformations to crystal order formation at 10 GPa pressure in the system.