Observation of phase fluctuations and electron-electron scattering in weakly disordered superconducting aluminum films

Phase fluctuations and electron-electron scattering in weakly disordered, two-dimensional superconducting Al films have been observed through their effects on the resistance of low-resistance Al-${\mathrm{AlO}}_{\mathrm{x}}$-Cu tunnel junctions. These are the uniform-film analog of the fluctuations in percolating films and in Josephson junctions. Disorder-enhanced electron-electron scattering has the magnitude and temperature dependence expected theoretically.