The Chiral Plaquette Polaron Paradigm (CPPP) for high temperature cuprate superconductors

A scientific revolution occurred in 1986–1994 in which the Tc for the best superconductors exploded from 23 K (Nb3Ge) to 138 K (Hg0.2Tl0.8Ba2Ca2Cu3O8.33). Despite enormous effort over the last 21 years, the superconducting mechanism remains unknown. All previous attempts assumed that the doped holes were in the CuO2 plane. We showed recently with improved quantum mechanics (QM) calculations that the hole is out of the CuO2 plane and delocalized over four Cu atoms in a square Plaquette that forms the basis of our Chiral Plaquette Polaron Paradigm (CPPP). Here, we show how very simple geometric arguments provide a qualitative understanding of the broad range of cuprate phenomenology. This simple geometric analysis may be useful in guiding the development of materials for improved superconductors. The CPPP suggests that judicious control of the dopant distribution could possibly lead to a room-temperature Tc.