UNIFYING THE PHASE-DIAGRAMS OF THE MAGNETIC AND TRANSPORT-PROPERTIES OF LA2-XSRXCUO4, SS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-SIMILAR-TO-0.05

An extensive experimental and theoretical effort has led to a largely complete mapping of the magnetic phase diagram of La2-xSrxCuO4, and a microscopic model of the spin textures produced in the x less than or similar to 0.05 regime has been shown ru be in agreement with this pha se diagram. Hen we use this same model to derive a theory of the impur ity-dominated, low-temperature transport. Then, we present an analysis of previously published data for two samples: x = 0.002 data from Che n et al., and x = 0.04 data from Keimer et al. We show that the transp ort mechanisms in the two systems are the same, even though they are o n opposite sides of the observed insulator-to-metal transition. Out mo del of impurity effects on the impurity-band conduction, variable-rang e-hopping conduction, and Coulomb-gap conduction is similar to that us ed to describe doped semiconductors. However, for La2-xSrxCuO4 we find that in addition to impurity-generated disorder effects, strong corre lations are important and must be treated on an equal level with disor der. On the basis of this work we propose a phase diagram that is cons istent with all available magnetic and transport experiments, and whic h connects the undoped parent compound with the lowest x-value for whi ch La2-xSrxCuO4 is found to be superconducting, viz. x approximate to 0.05.