Ferroelectric properties of RbNbO3 and RbTaO3

Abstract

Phonon spectra of cubic rubidium niobate and rubidium tantalate with the perovskite structure are calculated from first principles within the density functional theory. Based on the analysis of unstable modes in the phonon spectra, the structures of possible distorted phases are determined, their energies are calculated, and it is shown that $R3m$ is the ground-state structure of RbNbO3. In RbTaO3, the ferroelectric instability is suppressed by zero-point lattice vibrations. For ferroelectric phases of RbNbO3, spontaneous polarization, piezoelectric, nonlinear optical, electro-optical, and other properties as well as the energy band gap in the LDA and GW approximations are calculated. The properties of the rhombohedral RbNbO3 are compared with those of rhombohedral KNbO3, LiNbO3, and BaTiO3.

arXiv comment5 pages, 2 figures, 5 tables

References in corpus (5)

• First-Principles Determination of Chain-Structure Instability in KNbO${}_3$
• Ab initio calculations of phonon spectra in ATiO3 perovskite crystals (A = Ca, Sr, Ba, Ra, Cd, Zn, Mg, Ge, Sn, Pb)
• Ferroelectric phase transition in orthorhombic CdTiO3: First-principles studies
• Band offsets in heterojunctions between cubic perovskite oxides
• Crystal structure and properties of barium thorate BaThO${}_3$ from first principles

Cited by in corpus (1)

• High throughput thermal conductivity of high temperature solid phases: The case of oxide and fluoride perovskites