Structures and Low-Pressure High-Temperature Superconductivity of a SB-Based Hydride SBH₇

Exploring high-temperature superconductivity at lower pressures is the hot topic of hydride studies. For this, the structures, stability, electronic characteristics, phonon spectra, and electron-phonon interaction of a SB-based hydride SBH7 are investigated by first-principles calculations and structure search prediction. We predict that the Pbam phase of SBH7 with thermodynamic and dynamic stabilities is a high-temperature superconductor above 70 GPa. The superconducting transition temperature is about 109 K at 70 GPa and is improved to about 130 K at 90 GPa. The crystal structure of SBH7 shows that the stability at low pressure mainly results from the stronger bonding between B and H than between S and H atoms, especially the strong interaction between B and B atoms.