Strong superconducting strength in ε-PbBi microcubes

Abstract Single phase e-PbBi microcubes were synthesized using a simple thermal evaporation method. Synchrotron x-ray measurement of the crystal structure of the e-PbBi microcubes revealed a space group of P6 3 /mmc. Enhanced superconducting transitions were observed from the temperature dependent magnetization, showing a main diamagnetic Meissner state below a T C of ~8.66(2) K. An extremely strong superconducting strength ( α =2.51(1)) and electron-phonon constant ( λ EP =2.25) are obtained from the modified Allen and Dynes theory, which give rise to higher T C superconductivity in this type of structure. The electron–phonon coupling to low lying phonons is found to be the leading mechanism for the observed strong-coupling superconductivity in the PbBi system.