Thermochemical ranking and dynamic stability of TeO<inf>2</inf> polymorphs from ab initio theory

The ability to predict temperature-dependent properties of solids from ab initio theories alone has marked a fundamental step forward in realistic materials modeling. Here, we use density functional theory (DFT)-based thermochemistry to investigate crystalline tellurium dioxide (TeO2). While the DFT description of its polymorphs is challenging, we demonstrate that the inclusion of suitable dispersion corrections makes a thermochemical analysis and a correct stability ranking possible. Paratellurite (α-TeO 2), a technologically most important compound used in optical devices, is lowest in Gibbs free enthalpy in agreement with previous thermochemical experiments. While α-TeO2 exhibits a three-dimensional bonding network, the well-known mineral tellurite (β-TeO2) contains two-dimensional sheets; nonetheless, we demonstrate that both polymorphs are extremely similar in thermodynamic state functions and chemical bonding. The latter is analyzed with the crystal orbital Hamilton population (COHP) method and offered as a possible explanation for the small stability difference (