Bond length fluctuation in perovskite chromate SrCrO3

Perovskite chromate SrCrO3 containing Cr4+ ions shows anomalous electronic states and physical properties, which are believed to be related to the bonding instability, but this has not been confirmed directly in experiments up to now. In order to address this issue, the crystal structure and electronic structure of SrCrO3 are investigated by using transmission electron microscopy and first-principles calculations. The results demonstrate that there is no fourfold rotational symmetry in the selected area electron diffraction patterns along the three main zone axes of SrCrO3, which is inconsistent with an expected cubic structure. Moreover, the orientation-dependent electron energy-loss spectra demonstrate a clear correlation between the dissimilar spectra and the anisotropic effects derived from the crystal structure, and first-principles calculations support the experimental results. All this strongly supports the bonding instability of ambient pressure and temperature phase of SrCrO3 and highlights the important influence of bonding fluctuation on its electronic structure and transport properties. The influence of the core-hole effect and Hubbard potential on the theoretical spectra is further investigated.Perovskite chromate SrCrO3 containing Cr4+ ions shows anomalous electronic states and physical properties, which are believed to be related to the bonding instability, but this has not been confirmed directly in experiments up to now. In order to address this issue, the crystal structure and electronic structure of SrCrO3 are investigated by using transmission electron microscopy and first-principles calculations. The results demonstrate that there is no fourfold rotational symmetry in the selected area electron diffraction patterns along the three main zone axes of SrCrO3, which is inconsistent with an expected cubic structure. Moreover, the orientation-dependent electron energy-loss spectra demonstrate a clear correlation between the dissimilar spectra and the anisotropic effects derived from the crystal structure, and first-principles calculations support the experimental results. All this strongly supports the bonding instability of ambient pressure and temperature phase of SrCrO3 and highlights the i...