Topological properties and topological superconductivity in real materials have attracted intensive experimental and theoretical attentions recently. The topological electronic properties of pressure-induced superconductors ${\mathrm{BiH}}_2$ have been studied based on first-principles electronic structure calculations. Recent experiments have revealed that ${\mathrm{BiH}}_2$ exhibits five distinct phases under high pressure, our studies show that $Cmcm\text{−}{\mathrm{BiH}}_2, Pnma\text{−}{\mathrm{BiH}}_2, Pnnm\text{−}{\mathrm{BiH}}_2$, and $P{2}_1/m\text{−}{\mathrm{BiH}}_2$ are all topological metals defined on curved Fermi levels, while the $P{2}_1{2}_1{2}_1\text{−}{\mathrm{BiH}}_2$ holds Weyl points near the Fermi level. The topological surface states (TSSs) and Fermi arcs of ${\mathrm{BiH}}_2$ right cross the Fermi level and hold helical spin textures. Considering the fact that the ${\mathrm{BiH}}_2$ exhibit high superconducting transition temperatures ($T_c$) of $\sim 70$ K under pressure confirmed by recent experiments, the superconducting bulks will induce superconductivity in the TSSs via the proximity effect. Thus, the hydride superconductors ${\mathrm{BiH}}_2$ may provide a promising platform for exploring topological superconductivity and Majorana zero modes.

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• Electronic structure
• Topological superconductors
• Topological materials
• First-principles calculations