Structure, Lattice Dynamics, and Exchange Interaction in Lu2V2O7, Y2V2O7: an Ab Initio Approach

Ab initio calculations of the crystal structure and fundamental vibrations of vanadium pyrochlores Lu2V2O7 and Y2V2O7 are performed. The calculations are performed in the framework of the density functional theory (DFT) with the use of hybrid functionals. The ions involved in the vibrations are determined by the isotope substitution method. Values of the isotropic exchange interaction constant were calculated. Theoretical results for the crystal structure parameters, the vibrational frequencies, and the isotropic exchange interaction parameter are compared with the experimental data.