Abstract
The effect of pressure (0-75GPa) applied on RbTaO3 perovskite is investigated using density functional theory (DFT) and an indirect to direct band gap transformation is observed. The influence of band gap transformation on the corresponding electronic, optical and thermoelectric behaviors is analyzed. The application of modified Becke and Johnson (mBJ) potential confirms that most precise electronic properties are reported, because various other functionals compute properties not agreeing to the experiments. The increasing pressure suppresses the cubic unit cell dimensions, resultantly, the lattice constant decays. The reducing lattice constant results in strongly interacting states shifted in energy, due to which, the indirect band gap increases in the visible energy range and becomes direct at 75GPa illustrating potential optoelectronic applications. The thermoelectric characteristics investigated for RbTaO3 at 0GPa and 75GPa also reveal thermoelectric device applications.