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arXiv · 0807.0833

Temperature dependent optical conductivity of undoped cuprates with weak exchange

J. Malek·S. -L. Drechsler·U. Nitzsche·H. Rosner·H. Eschrig
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Abstract

The optical conductivity sigma(omega) is calculated at finite temperature T for CuO_2 chain clusters within a pd-Hubbard model. Data at T = 300 K for Li_2CuO_2 are reanalyzed within this approach. The relative weights of Zhang-Rice singlet and triplet charge excitations near 2.5 and 4 eV, respectively, depend strongly on T, and a rather dramatic dependence of sigma(omega) on the ratio of the first to second neighbor exchange integrals is predicted. On the basis of these results, information about exchange interactionsfor frustrated edge-shared cuprates can be obtained from T-dependent optical spectra. Our results are also relevant for magnetically weakly coupled wide-gap insulators in general.

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J. Malek, S. -L. Drechsler, U. Nitzsche, H. Rosner, H. Eschrig. 2008-07-05. Temperature dependent optical conductivity of undoped cuprates with weak exchange. https://doi.org/10.1103/physrevb.78.060508

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