The Role of Phonons and Oxygen Vacancies in Non-Cubic SrVO.

Combining neutron diffraction with pair distribution function analysis, we have uncovered hidden reduced symmetry in the correlated metallic perovskite, SrVO. Specifically, we show that both the local and global structures are better described using a GdFeO distorted (orthorhombic) model as opposed to the ideal cubic ABO perovskite type. Recent reports of imaginary phonon frequencies in the density functional theory (DFT)-calculated phonon dispersion for cubic SrVO suggest a possible origin of this observed non-cubicity.

Direct assignment of molecular vibrations via normal mode analysis of the neutron dynamic pair distribution function technique.

For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations.