Jahn-Teller effect on orbital ordering and dynamics in ferromagneticLaMnO3

We study the combined influence of superexchange interactions and coupling to lattice degrees of freedom of strongly correlated $e_g$ electrons in the ferromagnetic phase of ${\mathrm{LaMnO}}_3.$ Ionic displacements and orbital order are analyzed as a function of uniaxial pressure and the Jahn-Teller interactions. We report a large gap in the orbital excitation spectrum resulting from the lattice coupling which can lead to a strong confinement of holes in lightly doped ${\mathrm{LaMnO}}_3$ insulators.