Effect of Stress on Electronic, Optical, Elastic, and Mechanical Properties of Potassium Tantalum Oxide (KTaO3): A DFT Study

The primary purpose of this study is to perform a wide-ranging analysis of the electronic, optical, structural, elastic, and mechanical properties of cubic-structured potassium tantalum oxide (KTaO3) by applying different amounts of stress (0, 20, 40, and 60 GPa). The computational generalized gradient approximation technique is applied on cubic KTaO3 with the Perdew-Burke-Ernzerhof exchange-correlation functional. We found that applied stress causes an increase in bandgap from 1.624 eV to 1.871 eV. The partial densities of state for bulk potassium tantalum oxide (KTaO3), potassium (K), tantalum (Ta), and oxygen (O) are also predicted. In the valence band range, the dominant peaks of KTaO3 at 0 GPa, 20 GPa, 40 GPa, and 60 GPa are due to p-states. We found noteworthy variations in optical parameters such as absorption I(w), optical conductivity o-1(co) real and cr2(co) imaginary, dielectric function e1(co) real and e2(co) imaginary, loss function L(co), reflectivity R(co) and real/imaginary refractive index n(co) with varying stress ranging from 0 GPa to 60 GPa. The values of elastic constants are predicted (4.1741-3.8890 A) computationally using energy deformation equations when stress is applied at 0-60 GPa. Mechanical features including bulk modulus (161.0911-426.1323), shear modulus (99.4505-153.3127), and Young's modulus (247.4334-410.6864) increase with increasing stress. The Pugh, Poisson, and Frantsevich ratios show that the material is ductile from 20 GPa to 60 GPa, while at 0 GPa, the material is brittle. Anisotropy is observed in the estimated values of KTaO3. Moreover, our predicted results reveal that the chosen material is good for optoelectronic devices because it has a high refractive index and good absorption, reflectivity, and conductivity.