Lattice dynamics of FeSb2

TL;DR

This study combines first-principles DFT calculations and Raman spectroscopy to analyze the lattice dynamics of FeSb2, revealing phonon mode behaviors, mode mixing, and effects of Co doping, with good agreement between theory and experiment.

Contribution

It provides a comprehensive assignment of phonon modes in FeSb2 and explores the effects of doping and temperature on lattice dynamics using combined computational and experimental methods.

Findings

Good agreement between calculated and measured phonon energies

Strong mixing and intensity exchange of Ag modes between 210 K and 260 K

Increased mode repulsion with Co doping

Abstract

The lattice dynamics of FeSb2 is investigated by the first-principles DFT calculations and Raman spectroscopy. All Raman and infra-red active phonon modes are properly assigned. The calculated and measured phonon energies are in good agreement except for the B3g symmetry mode. We have observed strong mixing of the Ag symmetry modes, with the intensity exchange in the temperature range between 210 K and 260 K. The Ag modes repulsion increases by doping FeSb2 with Co. There are no signatures of the electron-phonon interaction for these modes.