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Hole stripe and orbital fluctuating state in LaMnO$_{3+δ}$ ($0.085\leq δ\leq0.125$) unveiled by Raman spectroscopy

Yu. G. Pashkevich·V. P. Gnezdilov·P. Lemmens·K. -Y. Choi·G. Güntherodt·A. V. Eremenko·D. Nabok·V. I. Kamenev·S. N. Barilo·S. V. Shiryaev·A. G. Soldatov
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Abstract

Giant softening by 30 cm$^{-1}$ of the 490- and 620-cm$^{-1}$ modes is observed by Raman scattering measurements below the Curie temperature of single crystalline LaMnO$_{3+δ}$ ($0.085\leq δ\leq0.125$). A pseudogap-like electronic continuum and a Fano antiresonance at 144 cm$^{-1}$ appear below the charge ordering temperature. This gives evidence for the presence of an orbital fluctuating state and the formation of a hole stripe, respectively. This is further corroborated by a unstructured broadening and shifting of multiphonon features with increasing doping $δ$. Our study suggests the significance of double exchange mechanism in the charged ordered insulating state.

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Yu. G. Pashkevich, V. P. Gnezdilov, P. Lemmens, K. -Y. Choi, G. Güntherodt, A. V. Eremenko, D. Nabok, V. I. Kamenev, S. N. Barilo, S. V. Shiryaev, A. G. Soldatov. 2005-06-13. Hole stripe and orbital fluctuating state in LaMnO$_{3+δ}$ ($0.085\leq δ\leq0.125$) unveiled by Raman spectroscopy. https://arxiv.org/abs/cond-mat/0506258

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