Lattice vibrations of alpha'-NaV2O5

Abstract

We have measured far infrared reflectance and transmittance spectra as well as Raman scattering spectra of α'-NaV2O5 single crystals for all the principal polarizations. The temperature range above the phase transition temperature T_c=35 K was investigated, mainly. On the basis of this experimental study and of the lattice dynamics calculations we conclude that the symmetry of NaV2O5 in the high temperature phase is described by the centrosymmetric D_{2h}^{13} space group. The assignment of the observed phonons is given. Values of dielectric constants are obtained from the infrared data. Asymmetric shapes of several infrared lines as well as higher order infrared vibrational spectra are discussed. The crystal field energy levels of the 3d electron localized at the V^{4+} site have been calculated in the framework of the exchange charge model using the values of effective charges obtained from the lattice dynamics calculations. According to the results of these calculations, the earlier observed broad optical bands in the region of 1 eV can be interpreted as phonon assisted d-d transitions.

12 pages, 8 figures, 5 tables; submitted to PRB

References in corpus (6)

• NaV_2O_5 as a quarter-filled ladder compound
• Experimental evidence for a spin-Peierls-transition in ${\alpha }^{\prime }-Na{V}_2{O}_5$
• Raman, infrared and optical spectra of the spin-Peierls compound NaV_2O_5
• Interference of a first-order transition with the formation of a spin-Peierls state in alpha'-NaV2O5?
• Study of spin-Peierls transition in alpha'--NaV2O5 by infrared reflectivity
• Appearance of new lines and change in line shape in the IR spectrum of a NaV_2O_5 single crystal at the spin-Peierls transition

Cited by in corpus (5)

• Optical spectroscopic study of the interplay of spin and charge in NaV2O5
• Lattice vibrations of alpha'-NaV_2O_5 in the low-temperature phase. Magnetic bound states?
• Optical properties, electron-phonon coupling, and Raman scattering of vanadium ladder compounds
• Optical properties of NaxV2O5
• Using electronic structure changes to map the H-T phase diagram of alpha'-NaV2O5