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

摘要

The superconducting transition temperatures T_c of face-centered cubic Al_(1-x)-Li_x 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.