Local pressures in Zn chalcogenide polymorphs

¹ Laboratoire de Physique Théorique, École Préparatoire Sciences et Techniques - B.P. 230, 13000 Tlemcen, Algeria
² Departamento de Química Física y Analítica, Universidad de Oviedo - Oviedo, Spain, EU
³ Laboratoire de Chimie Théorique, Université Pierre et Marie Curie - Paris, France, EU
⁴ Departamento de Química Física I, Universidad Complutense de Madrid - Madrid, Spain, EU
⁵ MALTA-Consolider Team

^a jmrecio@uniovi.es

Received: 8 March 2012
Accepted: 9 May 2012

Abstract

Using the rich polymorphism of ZnX (X: S, Se, Te) compounds, we show how local pressures can be unequivocally determined from i) first-principles total energy calculations, and ii) atomic volumes derived by means of topological analysis of crystalline electron densities. An analogy between atoms and mechanical resistors is put forward since these local pressures lead to the inverse of the thermodynamic pressure once their respective inverses are added up. Accordingly, we define the atomic-like mechanical conductance as a measure of the atomic volume reduction for energy unit under pressure, and prove that, in agreement with chemical hardness expectations, Zn has lower values than S, Se, and Te in all the polymorphs of the chalcogenide crystal family.