Electronic, optical and atomistic studies of PtSb2 and PtBi2

Abstract

Platinum group minerals are abundant in South Africa. Platinum is of great significance in catalytic applications and many other medical and pharmaceutical industries. Our studies of PtSb2 and PtBi2 were carried out using Density Functional Techniques, including LDA and GGA methods. We investigated the pressure dependences of lattice parameters and bond lengths of the materials. All these properties were shown to decrease with increasing pressure, in a linear fashion. Other features that were studied are the electronic properties like density of states (DOS) and optical properties to determine the type of material being studied. A set of interatomic potentials has been derived for the study of bulk and surface properties of PtSb2 using the GULP code (General Utility Lattice Program). These potentials have proved to be reliable since they reproduced bulk properties of PtSb2 such as lattice parameters and elastic constants. As there are no experimental studies on surfaces we have been able, for the first time, to calculate surface energies for the low index surfaces and found out that the most stable surface is the {100} Sb terminated one, with the energy of 0.933 J.m-2 and the least stable is the {111} Sb terminated surface with the energy of 2.586 J.m-2.