Evidence for polaronic supercarriers in the copper oxide superconductors La (sub 2-x)Sr (sub x)CuO(sub 4)

The results of magnetization and thermal expansion measurements on samples of the copper oxide superconductor La(sub 2-x)Sr(sub x)CuO(sub 4) are discussed. These characterize the oxygen-isotope effects on the carrier density and on the in-plane penetration depth. Results also showed that polaronic charge carriers exist and condense into Cooper pairs in high-temperature superconductors. It was also confirmed that a strong Jahn-Teller effect can result in the formation of these polarons.