Origin of the Optical Gap in Half-Doped Manganites

Abstract

We have analyzed the coexisting charge and orbital ordering in half-doped manganites using a model which includes Coulomb and Jahn-Teller orbital polarization interactions. Most surprisingly, the gap in the optical conductivity is reduced by both on-site and intersite Coulomb interactions, but increases and explains the experimental results when the Jahn-Teller terms with orbital polarization are considered. The origin of this behavior is explained within a molecular model which arises in the limit of extreme topological frustration, when single electrons are confined to molecular units consisting of three orbitals.

8 pages, 7 figures, 1 table to appear on Physical Review B

References in corpus (5)

• On charge and orbital ordering in La0.5Sr1.5MnO4
• Spin, charge and orbital ordering in La0.5Sr1.5MnO4
• Charge Ordering Fluctuation and Optical Pseudogap in La${}_{1-x}$Ca${}_x$MnO${}_3$
• Ferromagnetic zigzag chains and properties of the charge ordered perovskite manganites
• Coloumb interaction and instability of CE-structure in half doped manganites

Cited by in corpus (8)

• Spin-Orbital Order Modified by Orbital Dilution in Transition Metal Oxides: From Spin Defects to Frustrated Spins Polarizing Host Orbitals
• Doping dependence of spin and orbital correlations in layered manganites
• Manganites at Quarter Filling: Role of Jahn-Teller Interactions
• In-plane anisotropy of the electronic structure for the charge/orbital-ordered state in half-doped manganite with layered structure
• Spin-orbital physics in the optical conductivity of quarter-filled manganites
• Optical conductivity due to orbital polarons in systems with orbital degeneracy
• Signatures of electronic polarons in La${}_{1-x}$Sr${}_{1+x}$MnO${}_4$ observed by electron energy-loss spectroscopy
• Tuning Crystal Field Potential by Orbital Dilution in $d^4$ Oxides