NORMAL-STATE PHASE-DIAGRAM OF (LA,SR)(2)CUO4 FROM CHARGE AND SPIN DYNAMICS

The significant progress in elucidating the normal state of the prototypical cuprate La2-xSrxCuO4 is described. New insight is gained from quantitative charge dynamics studies (resistivity, Hall effect) over wide temperature and hole concentration ranges. Characteristic temperatures T* have been discovered and corresponding T*'s can also be identified in the magnetic response. At lowest carrier concentrations, T*'s start out high (700K-800K) and drop rapidly to similar to 100K when superconductivity disappears at high doping levels. From comparisons with other compounds, we suggest that the T* marks the development of a pseudogap in the excitation spectrum and we present a T*-x diagram for LSCO, which we suggest is generic to all hole doped layered cuprates.