Pressure dependent mechanical properties of europium mono chalcogenides under high pressure

A theoretical study of the elastic properties in EuX (X = O, S, Se, Te) using an effective interionic interaction potential in which long-range Coulomb as well charge transfer interactions, Hafemeister and Flygare type short- range overlap repulsion extended up to the second neighbor ions and van der Waals interactions are considered. Emphasis is on the evaluation of the pressure dependent Poisson's ratio nu, the ratio R-G/B of G (shear modulus) over B (bulk modulus), anisotropy parameter, Shear and Young's modulus, Lame constant, Klein man parameter, elastic wave velocity and thermodynamical property as Debye temperature. The Poisson's ratio behavior infers that europium chalcogenides are brittle in nature. To our knowledge this is the first quantitative theoretical prediction of the pressure dependence of elastic, and thermodynamical properties explicitly the ductile (brittle) nature of EuX and still awaits experimental confirmations. (C) 2012 Elsevier B.V. All rights reserved.