Crossover behavior of in-plane and out-of-plane resistivity in La 2− xSr xCuO 4

Abstract

We report that the in-plane ( ρ ab ) and out-of-plane ( ρ c ) resistivity of La214 deviate downward and upward from linear extrapolations of their high- T data below a certain temperature T*, respectively, which are very similar to the crossover behaviors of ρ ab and ρ c arising from the pseudogap formations in Y123 and Bi2212. The crossover behavior of resistivity in La214 occurs around T*∼ T co≡2 Δ o/4.3 k B as in Bi2212, where 2 Δ o is the superconducting gap magnitude at T≪ T c. These results suggest that a pseudogap may open up below T*∼ T co also in La214, although it has not been observed in microscopic experiments on La214.