Prediction of BaBiO${}_3$-like superconducting perovskites in K-doped SrAsO${}_3$

Abstract

Using first-principles calculations, we predict a new perovskite compound SrAsO${}_3$ . The undoped cubic phase has pronounced soft-phonon instabilities, which are gradually suppressed upon K doping the Sr site. The cubic phase becomes dynamically stable for K-doping levels above approximately 60%, and the stabilized K-doped phases are metallic with predicted conventional phonon mediated superconductivity. Moreover, the inclusion of nonlocal exchange interactions broadens the electronic bandwidth, enhances the electron-phonon coupling (EPC) strength, and increases the superconducting transition temperature ($T_c$) of these doped compounds. In particular, the HSE06 hybrid exchange-correlation functional corrected EPC constant $\lambda$ reaches 1.41 for Sr${}_{0.4}$K${}_{0.6}$AsO${}_3$, corresponding to a predicted $T_c$ of 44.3 K. These results suggest that SrAsO${}_3$ is a BaBiO${}_3$-like superconducting perovskite driven by strong electron-phonon coupling.