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arXiv · 1311.3191

Fano Resonances in the Infrared Spectra of Phonons in Hyper-Kagome Na_3Ir_3O_8

D. Pröpper·A. N. Yaresko·T. I. Larkin·T. N. Stanislavchuk·A. A. Sirenko·T. Takayama·A. Matsumoto·H. Takagi·B. Keimer·A. V. Boris
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Abstract

We report the complex dielectric function of high-quality Na_3Ir_3O_8 single crystals determined by spectroscopic ellipsometry in the spectral range from 15 meV to 2 eV. The far-infrared phonon spectra exhibit highly asymmetric line shapes characteristic of Fano resonances. With decreasing temperature, we observe a sharp increase of the infrared intensity of the Fano-shaped phonon modes accompanied by concomitant changes in the low energy electronic background, formed by electronic transitions between Ir 5d t_2g bands of a mostly J_eff = 1/2 character. The role of the complex Hyper-Kagome lattice structure and strong spin-orbit coupling is considered.

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D. Pröpper, A. N. Yaresko, T. I. Larkin, T. N. Stanislavchuk, A. A. Sirenko, T. Takayama, A. Matsumoto, H. Takagi, B. Keimer, A. V. Boris. 2013-11-13. Fano Resonances in the Infrared Spectra of Phonons in Hyper-Kagome Na_3Ir_3O_8. https://doi.org/10.1103/physrevlett.112.087401

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