First principle approach to substitutional effect of europium (Eu+2) on electronic and optical parameters of strontium pyroniobate for low temperature applications

Materials of the type A2B2O7 have remarkable ferroelectric, multiferroic and photocatalytic properties. Strontium pyroniobate (Sr2Nb2O7) was the first compound of this family that showed a high curie temperature, ferroelectric behavior at room temperature and extra ordinary piezo-, thermo- and pyro-electric properties. We have reported on first principles study of substitutional effect of europium (Eu+2) on strontium pyroniobate and its potential in low temperature electronics. The electrons were handled using GGA + U whereas calculations were carried out using DFT framework in WIEN2k. The calculated results show that doping induced a direct band gap of 1.193 eV and 1.082 eV for majority spin up states and 3.289 eV and 3.096 eV for minority spin down states in europium doped bulk and two-dimensional compounds, respectively. Furthermore, the optical dispersion of dielectric constant is in close agreement with our calculated electronic structure, and the main peak in energy lossless region for all investigated compounds is observed at 13 eV which can be related to Plasmon resonance peak. In general, computed results for two dimensional (2D) europium doped Sr2Nb2O7 proves its enhanced suitability and strong candidacy for low temperature applications. •The effect of Eu-doping on the properties of Sr2Nb2O7 has been investigated using the Density Functional Theory (DFT).•The exchange-correlation potential was calculated using the GGA+U.•The Eu-doping lead to a band gap narrowing, which enhances the visible light absorption.•Good enhancement of absorption and reflectivity in the visible region.