Optical conductivity in doped manganites with planar x${}^2$-y${}^2$ orbital order

Abstract

We investigate a planar model for the ferromagnetic (FM) phase of manganites, which develops orbital order of $e_g$ electrons with x${}^2$-y${}^2$-symmetry at low temperature. The dynamic structure factor of orbital excitations and the optical conductivity $\sigma (\omega )$ are studied with help of a finite-temperature diagonalization method. Our calculations provide a theoretical prediction for $\sigma (\omega )$ for the 2D FM state and are of possible relevance for the recently found A-type phase of manganites at high doping which consists of FM layers coupled antiferromagnetically. In the x${}^2$-y${}^2$ ordered regime $\sigma (\omega )$ shows both a Drude peak and a gapped incoherent absorption due to a gap in the orbital excitations.

5 pages, 5 figures, to appear in Phys. Rev. Lett

References in corpus (5)

• Optical Conductivity of Manganites: Crossover from Jahn-Teller Small Polaron to Coherent Transport in the Ferromagnetic State
• Polaron Absorption in a Perovskite Manganite La0.7Ca0.3MnO3
• Orbital dynamics in ferromagnetic transition metal oxides
• Optical conductivity of colossal magnetorestistance compounds: Role of orbital degeneracy in the ferromagnetic phase
• Orbital dynamics: The origin of the anomalous optical spectra in ferromagnetic manganites

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