DFT investigations of structural stability and structure dependent physical behavior of SnO2 polymorphs

Abstract

In this work, we investigated the electronic, mechanical and thermodynamic properties of various phases of SnO2 from first principles method. Here the five phases of choice are rutile, α-PbO2, CaCl2, pyrite, and ZrO2. To begin with, from the key parameters such as total energy, bond length and cohesive energy of the phases, we theoretically estimated their phase stability. Interestingly, the estimated elastic moduli are dependent on the corresponding crystal symmetry. These parameters are also comparable with reported values. Further, from the phonon dispersion relation, we recognized the dynamically stable phases. In addition, we also calculated the Debye temperature of the polymorphs from the average wave velocity, νm. Finally, we presented the relationship between the physical properties of the phases and their structural symmetry sequence. Such a relationship is not derived earlier in any theoretical and experimental report.