Systematic evolution of temperature-dependent resistivity inLa2−xSrxCuO4

Abstract

The in-plane resistivity (${\mathrm{\ensuremath{\rho}}}_{\mathit{a}\mathit{b}}$) of ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{CuO}}_{4}$ has been studied over a wide temperature (4--1000 K) and composition range (0x0.35). The much discussed T-linear resistivity is observed only in the narrow composition region associated with optimal superconductivity. In the underdoped range (x0.1), we observe first indications of resistivity saturation and analyze the resistivity as indicative of a ``small'' Fermi surface. In the overdoped range (x>0.2), ${\mathrm{\ensuremath{\rho}}}_{\mathit{a}\mathit{b}}$ follows a novel power-law dependence, \ensuremath{\rho}\ensuremath{\infty}${\mathit{T}}^{1.5}$, over the entire temperature range up to 1000 K.