biostudies-literatureGriffitt SDOE | SC | Basic Energy Sciences (BES)845https://www.ebi.ac.uk/biostudies/studies/S-EPMC9931700biostudies-literatureUnknown14(1)The doped perovskite BaBiO₃ exhibits a maximum superconducting transition temperature (T_c) of 34 K and was the first high-T_c oxide to be discovered, yet pivotal questions regarding the nature of both the metallic and superconducting states remain unresolved. Although it is generally thought that superconductivity in the bismuthates is of the conventional s-wave type, the pairing mechanism is still debated, with strong electron-phonon coupling and bismuth valence or bond disproportionation possibly playing a role. Here we use diffuse x-ray scattering and Monte Carlo modeling to study the local structure of Ba_1-xK_xBiO₃ across its insulator-metal boundary. We find no evidence for either long- or short-range disproportionation, Nature communicationsLocal inversion-symmetry breaking in a bismuthate high-T_c superconductor.PMC9931700DE-SC0016371Zhai DGreven MGriffitt SPelc DSpaic MKrogstad MJOsborn RAnderson ZWJoe JfalseLocal inversion-symmetry breaking in a bismuthate high-T_c superconductor.The doped perovskite BaBiO₃ exhibits a maximum superconducting transition temperature (T_c) of 34 K and was the first high-T_c oxide to be discovered, yet pivotal questions regarding the nature of both the metallic and superconducting states remain unresolved. Although it is generally thought that superconductivity in the bismuthates is of the conventional s-wave type, the pairing mechanism is still debated, with strong electron-phonon coupling and bismuth valence or bond disproportionation possibly playing a role. Here we use diffuse x-ray scattering and Monte Carlo modeling to study the local structure of Ba_1-xK_xBiO₃ across its insulator-metal boundary. We find no evidence for either long- or short-range disproportionation, 2023-01-01T00:00:00Z2023 Feb2025-04-05T10:36:10.481Z2025-04-05T10:36:10.481ZS-EPMC99317003679258210.1038/s41467-023-36348-9