Evolution of the resistivity of single-layer Bi 2Sr 1.6La 0.4CuO y thin films with doping and phase diagram

Abstract

The temperature dependence of the in-plane resistivity ρ( T) is measured on epitaxial c-axis oriented single-layer Bi 2Sr 1.6La 0.4CuO y thin films at various oxygen concentrations. By successive annealing treatments, the oxygen content of the same film is changed from maximally overdoped to strongly underdoped non-superconducting state, passing through the optimal state with T c max =30 K . The underdoped states show a downturn of the resistivity from the high T-linear behavior below a characteristic temperature T*, signature of the pseudogap effect. T* appears near optimally doped state and increases sharply with decreasing carrier concentration. Two other characteristic temperatures are observed in ρ( T) for underdoped states: the temperature T I of the inflection point in ρ( T) ( T I∼0.5 T *) and the temperature T M corresponding to the onset of localization effects. A phase diagram T versus doping is established.