Ground state structure ofBaZrO3: A comparative first-principles study

摘要: First-principles calculations, based on density-functional theory, are exploited to investigate the nature of ground-state structure barium zirconate. The experimentally observed simple-cubic is found be dynamically unstable against an antiferrodistortive transformation. This instability manifests itself through imaginary frequency modes along whole R-M edge Brillouin zone. computations predict orthorhombic crystal material, only slightly distorted from cubic lattice, with eight times larger unit cell and alternate ${\text{ZrO}}_{6}$ octahedra rotated in opposite directions around Cartesian axes. apparent disagreement some previous first-principles results regarding considered detail. neglect $5{s}^{2}$ $5{p}^{6}$ electrons valence configuration Ba responsible for previously reported erroneous results.