Abstract

Purpose. Nowadays, the indium selenides have attracted increasing attention since they are potential candidates for the applications of their physical properties in many devices. In particular, in the In₄Se₃ semiconductor, it was revealed a high thermoelectric figure of merit that opens its perspectivity for thermoelectrics. In the single layer of InSe, the unusual transport phenomena and optical properties have been observed. For both crystals, these anomalies are connected with the strong electron-phonon coupling owing to the peculiar character of electron states and their interaction with phonons. Therefore, for the bulk In₄Se₃ and β-InSe crystals, it is of interest to study the electron-phonon coupling which can play an important role in the physical properties of considered materials. The main aim of our paper is to carry out the investigation of the evolution of the electron-phonon interaction at the transition from the β-InSe crystal to the In₄Se₃.
Methods. The program packet ABINIT with the application of the updated methodology of the density functional perturbation theory (DFPT).
Results. In our work, we calculated the phonon spectra, density of phonon states, the Eliasberg spectral function 2F(ω), and electron-phonon coupling strength. The phonon linewidths Γ_el−ph for phonon wavevectors along high symmetry directions in the Brillouin zone are obtained too.
Conclusion. According to our estimations, the parameters of electron-phonon interaction for In₄Se₃ are higher than for β-InSe that indicates an increase in energy exchange between vibrational and electronic states. This fact is connected  with the stronger interaction between the corrugated layers and more complicated chemical bonding topology in In₄Se₃ in comparison with the β-InSe layered crystal. The main contribution in these characteristics is due to the high-frequency optical vibrations which are responsible for the oscillations in the perpendicular direction to the planes of the layers

Keywords: indium selenides, electron-phonon interaction, first principles calculations, Eliashberg spectral function

Suggested citation