  Planar large-bipolarons can form if the ratio of the surrounding mediums
static to high-frequency dielectric constants is especially large. A
large-bipolaron in p-doped La2CuO4 is modeled as two electrons being removed
from the out-of-plane orbitals of four oxygen ions circumscribed by four copper
ions of a CuO2 layer. These oxygen dianions relax inwardly as they donate
electrons to the surrounding outwardly relaxing copper cations. This charge
transfer generates the strong in-plane electron-lattice interaction needed to
stabilize a large-bipolaron with respect to decomposing into polarons. The
lowest-energy radial in-plane optic vibration of a large-bipolarons four core
oxygen ions with their associated electronic charges has d-symmetry. Electronic
relaxation in response to multiple large-bipolarons atomic vibrations lowers
their frequencies to generate a phonon-mediated attraction among them which
fosters their condensation into a liquid. This liquid features distinctive
transport and optical properties. A large-bipolaron liquids superconductivity
can result when it undergoes a Bose condensation yielding macroscopic
occupation of its ground-state. The synchronized vibrations of large-bipolarons
core-oxygen ions with their electronic charges generate this Bose condensates
dynamic global d-symmetry.
