β–RhPb2: A topological superconductor candidate

Abstract

A topological superconductor candidate β−RhPb2 is predicted by using first-principles electronic structure calculations. Our calculations show that there is a band inversion around the Fermi level at the Z point of Brillouin zone. The calculated nonzero topological invariant Z2 indicates that β−RhPb2 is a topological insulator defined on a curved Fermi level. Slab calculations further demonstrate that the gapless nontrivial topological surface states (TSS) are not overlapped by the bulk states and they cross the Fermi level. Phonon calculations confirm the dynamical stability of β−RhPb2, while electron-phonon coupling (EPC) calculations predict that the superconducting transition temperature (Tc) of β−RhPb2 can reach 9.7 K. The coexistence of nontrivial topological band structure with the TSS crossing the Fermi level as well as the superconducting Tc above the liquid-helium temperature suggest that the layered compound β−RhPb2 is a topological superconductor, which deserves further experimental verification.

Source-reported materials — not catalogue approval

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