Two-dimensional weak localization effects in high temperature superconductor Nd2−x CexCuO4−δ

Abstract

A systematic study of the resistivity and Hall effect in single crystal Nd{2-x}Ce{x}CuO{4-d} films (0.12 < x < 0.20) is presented, with special emphasis on the low-temperature dependence of the normal state conductance. Two-dimensional weak localization effects are found both in a normally conducting underdoped sample (x = 0.12) and in situ superconducting optimally doped (x = 0.15) or overdoped (x = 0.18) samples in a high magnetic field B > B{c2}. The phase coherence time and the effective thickness of a CuO{2} conducting layer {d} (~ 1.5 A) have been estimated by fitting 2D weak localization theory expressions to the magnetoresistivity data for magnetic fields perpendicular to the {ab} plane and in plane. Estimates of the parameter {d} ensure the condition of strong carrier confinement and justify a model consisting of almost decoupled 2D metallic sheets for the Nd{2-x}Ce{x}CuO{4-d} single crystal.