First-principles study on the lattice dynamics of FeSb2

The lattice dynamics of FeSb2 are investigated by first-principles calculations based on a plane wave pseudopotential method. Phonon spectrum and the electron–phonon linewidths at the ΓΓ-point are obtained using the density-functional perturbation theory within the linear response method. Nine phonon modes are in good agreement with the experimental data, but the B3gB3g mode shows unusually large disagreement. In order to investigate the possibility of anharmonicity of phonon modes, frozen phonon calculations have been performed for the B1g1, B1g2 and B3gB3g modes. But the results are all equal to the density-functional perturbation theory calculations, indicating that the phonons are all harmonic. Our calculated electron–phonon linewidth of the B1g1 mode is consistent with experimental data, and we also confirm the existence of electron–phonon interactions for the Ag1, B1g1, and B1uB1u modes in FeSb2.

► Our result supports the Ag1 mode assignment of Refs. [11] and [12]. ► Nine phonon modes are in good agreement with the experimental data. ► The B3gB3g mode shows a relatively large discrepancy. ► Frozen phonon calculations of B1g1, B1g2 and B3gB3g modes show that they are all harmonic. ► We provide support for the existence of e-ph interactions for Ag1, B1g1, and B1uB1u modes.