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

Ever since high-T_c 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.