Incommensurate Orbital Order and Two-Phase Coexistence in Doped Manganites at Metal–Insulator Phase Boundary

We investigate theoretically the structural aspect of the characteristic features in the vicinity of the metal–insulator phase boundary in perovskite-based manganites. We develop a phenomenological treatment based on Ginzburg–Landau type formalism in which the elastic energies such as Jahn–Teller energy, phonon energy and the bulk strain energy are explicitly taken into account. The two important features observed commonly at the phase boundary; incommensurate orbital order and two-phase coexistence are reproduced as the stable states in the two dimensional model system.