Full potential linearized augmented plane wave investigations of structural and electronic properties of pyrochlore systems

摘要

The structural and electronic properties of La_(2)Zr_(2)O_(7) and La_(2)Hf_(2)O_(7) pyrochlore compounds were investigated using the first principles full-potential linearized augmented plane wave method within the density functional theory. In this approach, the generalized gradient approximation was used for the exchange-correlation potential. We have optimized the internal structure parameter and then calculated the ground-state energy, the lattice constant, the bulk modulus, and its pressure derivative. The interatomic distances and angles were also determined. The results are in good agreement with available experimental measurements. Our electronic structure calculations predict a direct band gap at the Γ point; the nature of chemical bonding is dominated by the presence of ionic character. Furthermore, both La_(2)Zr_(2)O_(7) and La_(2)Hf_(2)O_(7) compounds are found to be insulating, which is in good agreement with experimental data.