The Role of Quantum Interference Effects in Normal-State Transport Properties of Electron-Doped Cuprates

The normal-state resistivity of thin films of the infinite-layer electron-doped cuprate Sr<inf>1-x</inf>La<inf>x</inf>CuO<inf>2±?</inf> has been investigated. Under-doped samples, which clearly show a metal-to-insulator transition (MIT) at low temperatures, have allowed the determination of the fundamental physical mechanism behind the upturn of the resistivity, namely the quantum interference effects (QIEs) in three-dimensional systems. The occurrence of weak localization effects has been unambiguously proven by low-frequency voltage spectral density measurements, which show a linear dependence of the 1/f noise on the applied bias current at low temperatures. The identification of the QIEs at low temperatures has therefore allowed the determination of the high-temperature non-Fermi liquid metallic phase, which is dominated by a linear temperature dependence of the resistivity for all of the samples investigated.