Comment on "high-pressure synthesis of orthorhombic SrIrO₃ perovskite and its positive magnetoresistance" [J. Appl. Phys. 103, 103706 (2008)]

In their article, Zhao et al. report the synthesis of SrIrO₃ at high temperature and high pressure [J. Appl. Phys. 103, 103706 (2008)]. Under these conditions, the crystal structure of SrIrO₃ can be stabilized as an orthorhombic perovskite with space group Pnma. They refine the lattice parameters and list the Wyckoff orbits and atomic coordinates. We believe that Zhao and coworkers made an unintentional error in reporting the crystal structure, which may adversely affect the description of the electronic structure. Indeed, we show the reported structure does not define a standard perovskite with nearly rigid IrO₆ octahedral tilts and rather exhibits a structural discrepancy with respect to the equilibrium structure obtained from density functional calculations.