In search of the ground-state crystal structure of Ta2O5 from ab initio and Monte Carlo simulations

Tantalum oxides (Ta2O5) are characterized by attractive physical and chemical properties, such as high dielectric constants anti-reflection behaviour. In principle, their electronic properties can be accurately investigated from first-principles simulations. However, the existence of several stable polymorphs these represents a major difficulty to calculate disentangle respective spectral features. To determine ground-state structure thermally grown oxide, we use linear-response time-dependent density functional theory calculations for investigating energy loss function in optical limit various polymorphs. We show that experimental signal, extracted reflection spectra (REELS) recorded on thin film, rationalized interpreted assuming ?-phase Ta2O5 underlying structural model oxide. find inclusion both local field effects spin–orbit coupling is crucial compute materials. Finally, further validate ?-Ta2O5 polymorph tantalum REELS using Monte Carlo approach, finding an excellent agreement with as-acquired data.