Lattice instabilities and structural phase transformations in La2CuO4 superconductors and insulators

摘要

Soft-mode structural phase transformations, common in many perovskite-based materials, are also found in La(sub 2)CuO(sub 4) and structurally related oxides. The resulting phase behavior is rather complex, but is a natural consequence of the degeneracy of the soft phonon order parameters. This paper reviews the structural and lattice-dynamical results and their interpretation based upon mean-field statistical mechanical models.