van Hove singularities and tight-binding model in high-temperature superconductor H3Se

- Electronic structures of H3Se have been studied using DFT calculations.
- Superconductivity-related van Hove singularities near Fermi level have been found.
- An accurate tight-binding model based on Wannier functions has been proposed.
- Phonon dispersions and vibration modes of H3Se have been discussed.

Ever since high-Tc superconductivity was found in H3S at 203 K under 200 GPa pressure, researches on hydrogen-rich family including H3S, H3P, and H3Te have been intensively carried out. Among those compounds, H3Se is a promising candidate of the same space group with H3S. In this work, we have thoroughly studied the electronic and phonon structures of H3Se using density functional theory (DFT) calculations. It is demonstrated that the electronic bands of H3Se contain van Hove singularities near the Fermi energy, which play a significant role in the superconductivity of this material. Besides, an accurate tight-binding model is proposed based on the Wannier function interpolations which can capture the main features of the electronic structures of H3Se. Moreover, we have also discussed the phonon dispersions and vibration modes for a better understanding of the phonon-electron interaction in H3Se.