Electronic phase diagram of La 2− xSr xCuO 4

Abstract

In this article, we discuss the electronic phase diagram of a high- T c cuprate La 2− x Sr x CuO 4; namely, how the electronic property changes as functions of temperature T and hole-doping level p. In particular, we focus on four crossover lines, which can be seen in the T dependences of uniform magnetic susceptibility and electronic specific heat. One of them is crossover line T a ( p) in the low doping region below p∼0.05 near the margin of the superconducting regime, which is associated with strongly developed antiferromagnetic (AF) spin correlations within the Cu–O planes. The others are crossover lines T max( p), T ∗(p) and T sf( p) in the normal state in the superconducting regime (0.05< p<0.27); T max >T ∗>T sf >T c. It is suggested that crossover lines T max( p), T ∗(p) and T sf( p) will be associated with the gradual developments of AF spin correlations, a kind of precursor of superconductivity and superconducting critical fluctuations, respectively.