Superconductivity in an organobismuth molecule*

Recently, novel quantum phenomena such as topological insulators and superconductors were suggested in organobismuth compounds. However, evidence for superconductivity from the zero-resistivity state in any organometallic compound has not been achieved yet, though much effort has been made. Here, we report the experimental realization of superconductivity in a critical temperature of 3.6 K in potassium-doped tri-o-tolylbismuthine, with evidence of both the Meissner effect and the zero-resistivity state through dc and ac magnetic susceptibility and resistivity measurements. The superconducting phase and its composition are determined by combined studies of X-ray diffraction and theoretical calculations as well as Raman spectroscopy measurements. These findings enrich the applications of organometallic compounds in superconductivity and add a new electron-acceptor family of organic superconductors.