First principles calculations of the physical properties of orthorhombic HfxA1-xO2 (A = Zr, Ti)

The paper evaluates the structural, electrophysical and mechanical properties of IV-B dioxides and the HfxA1-xO2 compound (A = Zr, Ti) by the density functional theory method in the Quantum ESPRESSO software package. It is established that orthorhombic TiO2 titanium dioxide does not exhibit ferroelectric properties, has a narrow band gap and a high value of dielectric permittivity compared with orthorhombic hafnium and zirconium dioxides. The introduction of zirconium atoms into the hafnium dioxide unit cell does not cause significant changes in the structure, leads to a decrease in the band gap and an increase in residual polarization. Compounds of the type HfxZr1-xO2 (x = 0.25, 0.5) have a high value of the elastic modulus, compared with stoichiometric HfO2 and ZrO2.