Superconductivity and phase stability of potassium-doped biphenyl

Phenyl molecules are proposed as potential high-temperature superconductors due to exhibiting interesting properties. Here, we report the discovery of superconductivity with the critical temperature (Tc) of ∼7.2 Kelvin in potassium (K)-doped biphenyl (C12H10). The dc magnetic susceptibility measurements provide solid evidence for the presence of the Meissner effect in KxC12H10. The Raman spectra detected bipolaronic characteristics in this superconducting state, which are proposed to account for the electron pairing. Theoretical simulations provided the information of the crystal structure of KxC12H10. Combining XRD data with formation energy, we suggest that the superconducting phase corresponds to K2C12H10 or with a small charge fluctuation in a layered structure. The discovery of superconductivity in K-doped biphenyl vastly expands the potential applications in the superconducting field.