arXiv subjects

A. E. Nikiforov

Publications and source records attributed to A. E. Nikiforov.

3 recordsLinked to original sources

arXiv2007

Magnetic resonance as an orbital state probe

Magnetic resonance in ordered state is shown to be the direct method for distinguishing the orbital ground state. The example of perovskite titanates, particularly, LaTiO3 and YTiO3, is considered. External magnetic field resonance spectra of these crystals reveal glaring qualitative dependence on assumed orbital state of the compounds: orbital liquid or static orbital structure. Theoretical basis for using the method as an orbital state probe is grounded.

cond-mat.str-el↗

arXiv2003

A possible demonstration of cooperative dynamical Jahn-Teller effect in Raman scattering spectrum of rhombohedral $LaMnO_3$

The Raman scattering (RS) spectra of rhombohedral $LaMnO_3$ is considered. It is shown that broad high intensity RS line at 640 $cm^{-1}$ could be explained in the framework of cooperative dynamical Jahn-Teller effect. This hypothesis is illustrated through the lattice dynamics calculations explicitly allowing for the electron-phonon term both in crystal energy and in dynamical matrix. The averaging scheme for the one mode cooperative dynamical effect is proposed

cond-mat.str-el↗

arXiv2002

Crystal structure of mixed fluorites Ca(1-x)Sr(x)F(2) and Sr(1-x)Ba(x)F(2) and luminescence of Eu(2+) in the crystals

Within the framework of the virtual crystal method implemented in the shell model and pair potential approximation the crystal structure of mixed fluorites Ca(1-x)Sr(x)F(2) and Sr(1-x)Ba(x)F(2) has been calculated. The impurity center Eu(2+) and the distance Eu(2+)-F in this crystals have been also calculated. The low level position of excited 4f65d configuration of the Eu(2+) ion has been expressed using phenomenological dependence on distance E(2+)-F. The dependences of Stokes shift and Huang-Rhys factor on concentration x have been received for yellow luminescence in Sr(1-x)Ba(x)F(2):Eu(2+). The value x, for which the eg -level of Eu(2+) ion will be in conduction band in Sr(1-x)Ba(x)F(2):Eu(2+) has been calculated.

cond-mat.mtrl-sci↗