Physical properties of KTaO3 compound for optoelectronic and thermoelectric applications: A DFT study

Abstract

The structural, electronic, optical and thermoelectric (TE) characteristics of cubic KTaO3 pervoskite are investigated at 0, 40, 80 and 150 GPa pressures by employing the full potential linearized augmented plane waves (FP-LAPW) scheme. The applied pressure has been found tailoring the characteristics of band gap (Eg) from indirect to direct at 150 GPa. A significant increase in the Eg has also been observed with rise of pressure. Moreover, In optical characteristics, the largest values of α(ω) are achieved in the ultraviolet range at 6.11, 7.22, and 7.99 eV for 0, 40, 80, correspondingly. The static values of refractive index n(0) are obtained as 2.31 (at 0 GPa), 2.29 (at 40 GPa), 2.25 (at 80 GPa) and 2.23 eV (at 150 GPa). Meanwhile, the BoltzTraP code is used to figure out the thermoelectric (TE) characteristics. Results indicated that power factor (PF) reached to its greatest value of 11 × 1012 W/K2.cm.s at 80 GPa. At all pressures, the value of seebeck coefficient (S) is increases with temperature and gained a maximum value of 175 (μ V/K) at 150 GPa and 800 K. The outcomes recommend the application of KTaO3 compound for optoelectronic and TE gadgets.