First-principles calculations of phonons, optical properties and Raman spectra in vanadium ladder compounds

Abstract:

The vanadium ladder compounds XV2O5 (X=Na,Ca,Mg) have been drawing attention in the solid state community for about 15 years. They belong to the active research area of complex materials with low-dimensional features, where charge, spin and lattice degrees of freedom strongly interact and lead to extraordinary physical properties. We have investigated the interplay of charge and lattice vibrations using ab-initio calculations based on density functional theory. In order to do so, we have first calculated the eigenfrequencies and eigenvectors of the Г point phonon modes. Then we have calculated the frequency dependent dielectric function and Raman intensities for the Raman active modes. I will present the methodology used in our work and the obtained results, and compare them to experiment. Finally I will discuss how our calculations can contribute to a better understanding of the physics in the investigated material systems.