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Exchange interaction effects on the optical properties of LuMnO3

A. B. Souchkov·J. R. Simpson·H. D. Drew·M. Quijada·H. Ishibashi·N. Hur·J. S. Ahn·S. W. Cheong·A. J. Millis
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Abstract

We have measured the optical conductivity of single crystal LuMnO3 from 10 to 45000 cm-1 at temperatures between 4 and 300 K. A symmetry allowed on-site Mn $d$-$d$ transition near 1.7 eV is observed to blue shift (~0.1 eV) in the antiferromagnetic state due to Mn-Mn superexchange interactions. Similar anomalies are observed in the temperature dependence of the TO phonon frequencies which arise from spin-phonon interaction. We find that the known anomaly in temperature dependence of the quasi-static dielectric constant epsilon_0 below the T_N ~90 K is overwhelmingly dominated by the phonon contributions.

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A. B. Souchkov, J. R. Simpson, H. D. Drew, M. Quijada, H. Ishibashi, N. Hur, J. S. Ahn, S. W. Cheong, A. J. Millis. 2003-06-23. Exchange interaction effects on the optical properties of LuMnO3. https://doi.org/10.1103/physrevlett.91.027203

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