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Abstract:
We investigate the spectral functions and orbital-correlation
functions relative to the position of an e(g) hole moving in
the ferromagnetic plane of orbitally ordered LaMnO3. Solving
this problem in a self-consistent Born approximation, we
analyze a hole motion as a function of uniaxial pressure, the
Jahn-Teller interaction, and the polarization of orbitals in
the vicinity of the hole. We report a large redistribution of
the spectral weight as compared with the free hole dispersion
(proportional tot), strongly dependent on the type of the
alternating orbital order. Polarization of orbitals around the
hole (proportional toDelta) can lead to a very narrow
quasiparticle band and to large incoherent spectral weight,
indicating a confinement of holes in a lightly doped LaMnO3
insulator. It thus strongly modifies the shape of the orbital
polaron, and favors the localization of small orbital polarons
in the regime of Delta>t.
