Intrinsic heterogeneity and polaron formation in high temperature superconducting copper oxides

A variety of unconventional isotope and lattice effects have been observed in high temperature superconducting copper oxides (HTSC), which do not find an explanation within models based on strong correlations only. It is shown here, that polaron formation is the origin of these experimental findings. The polaron formation is, however, not homogeneous, but restricted to limited spatial regimes thus leaving the antiferromagnetic background partially intact and allowing for the coexistence of different ground states.