A new mechanism is proposed to explain high-$T_c$ superconductivity in copper-oxide-based, open perovskitelike systems. It is shown that, should the oxygen ions be moving in a double-well potential, an order-of-magnitude enhancement of the electron-lattice coupling follows automatically from a consistent treatment of this motion. Both theoretical and experimental evidence for the presence of such double wells is cited.

• Received 13 July 1987

DOI:https://doi.org/10.1103/PhysRevLett.60.2191