Spectroscopy of condensed matter

Phonon spectrum and elastic properties of Gd$_2$Sn$_2$O$_7$: ab initio calculation

V. A. Chernyshev^a, K. I. Glukhov^a, P. A. Zayats<sup>b

a</sup> Ural Federal University named after the First President of Russia B. N. Yeltsin, Yekaterinburg, Russia
^b Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia

Abstract: The phonon spectrum of gadolinium stannate Gd$_2$Sn$_2$O$_7$ was calculated within the ab initio approach. The frequencies and types of phonon modes active in infrared absorption and Raman scattering were determined. The degree of ion participation in phonon modes was determined from the analysis of displacement vectors that was obtained in the first-principles calculation. The elastic constants and hardness of Gd$_2$Sn$_2$O$_7$ were calculated. The effect of hydrostatic pressure on the frequencies of fundamental vibrations was studied. The calculations were carried out within the MO LCAO approach with hybrid functionals that take into account the contribution of nonlocal exchange in the Hartree-Fock formalism. Our results also demonstrate the possibility of using a pseudopotential to describe the inner shells of a rare-earth ion.

Keywords: rare earth stannates, phonons, elastic constants, hybrid functionals.

Received: 24.01.2024
Revised: 10.07.2024
Accepted: 22.07.2024

DOI: 10.61011/OS.2024.07.58895.5781-24

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