Superconducting transition parameters in aluminum–lithium alloys (0–10 at.% Li)

The superconducting transition temperatures T c of face-centered cubic Al1−x–Lix alloys ( x = 0 – 0.10 ) exhibit a minimum near x = 0.03 (3 at.% Li). The McMillan strong-coupling T c equation yields a similar trend of the electron–phonon coupling constant λ . Meanwhile, the density of states at the Fermi level N ( 0 ) decreases monotonically with increasing x . It appears that T c drops initially due to a reduced N ( 0 ) , which is then overtaken by alloying-enhanced factors of phonon or electron–phonon interaction.