Electron-electron interaction dominated quantum transport in thick CuGe films

We have successfully made a series of thick Cu _x Ge _100-x films spanning the weakly and strongly localized regimes. With decreasing mole concentration of Cu relative to Ge, the resistivity of film becomes bigger at a given temperature and demonstrates a stronger temperature dependence at low temperatures. When x is big, 46 ≤ x ≤ 56, resistivity increases with the square root of the decreasing temperature, implying a weak-disorder behavior. For x small, 14 ≤ x ≤ 20, resistivity increases exponentially with decreasing temperature, implying a strongly localized behavior. The results show that the low-temperature transport in these films is dominated by the disorder enhanced electron-electron interaction effects.