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arXiv · 0801.4650

Electron-phonon interaction in the lamellar cobaltate Na$_x$CoO$_2$

A. Donkov·M. M. Korshunov·I. Eremin·P. Lemmens·V. Gnezdilov·F. C. Chou·C. T. Lin
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Abstract

We study theoretically and experimentally the dependence of the electron-phonon interaction in Na$_x$CoO$_2$ on the sodium concentration $x$. For the two oxygen phonon modes found in Raman experiments, $A_{1g}$ and $E_{1g}$, we calculate the matrix elements of the electron-phonon interaction. Analyzing the feedback effect of the conduction electrons on the phonon frequency we compare the calculated and experimentally observed doping dependence of the $A_{1g}$ mode. Furthermore, due to the momentum dependence of the electron-phonon coupling for the $E_{1g}$ symmetry we find no renormalization of the corresponding phonon frequency which agrees with experiment. Our results shed light on the possible importance of the electron-phonon interaction in this system.

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A. Donkov, M. M. Korshunov, I. Eremin, P. Lemmens, V. Gnezdilov, F. C. Chou, C. T. Lin. 2008-01-30. Electron-phonon interaction in the lamellar cobaltate Na$_x$CoO$_2$. https://doi.org/10.1103/physrevb.77.100504

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