LAPW frozen-phonon calculation, shell model lattice dynamics and specific-heat measurement of SnO

TL;DR

This study combines ab-initio LAPW calculations, shell-model lattice dynamics, and specific heat measurements to accurately characterize phonon modes and thermal properties of SnO, resolving previous mode assignments and validating models against experimental data.

Contribution

It introduces a new shell-model for SnO that aligns well with LAPW calculations and experimental measurements, improving understanding of its lattice dynamics and thermal behavior.

Findings

LAPW calculations correctly assign E$_g$ symmetry to the 113 cm$^{-1}$ mode.

Shell-model frequencies agree with experimental Raman data.

Computed specific heat matches measurements across 5-110 K.

Abstract

An ab-initio Linear Augmented Plane-Wave (LAPW) calculation of the zone-centered phonon frequencies of SnO has been performed. E$_g$ symmetry has been ascribed to the mode observed at 113 cm$^{-1}$ in Raman measurements, discarding a previous B$_{1g}$ assignement. The other phonon modes measured by Raman spectroscopy are also well reproduced. A new shell-model has also been developed, that gives good agreement of the zone-centered frequencies compared to the measured data and the LAPW results. Specific heat measurements have been performed between 5 K and 110 K. Computation of the specific heat and the M\"{o}ssbauer recoilless fraction with the improved shell-model shows a good agreement with the experimental data as a function of temperature.