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arXiv · 1405.6781

Electron-phonon coupling in the superconducting single crystal Rb$_{0.8}$Fe$_{1.68}$Se$_2$

B. Xu·Y. M. Dai·J. Han·K. Wang·R. Yang·Y. X. Yang·W. Zhang·H. Xiao·X. G. Qiu
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Abstract

The optical properties of the superconducting single crystal Rb$_{0.8}$Fe$_{1.68}$Se$_2$ with $T_{c}$ $\simeq$ 31 K have been measured over a wide frequency range in the $ab$ plane. We found that the optical conductivity is dominated by a series of infrared-active phonon modes at low-frequency region as well as several other high-frequency bound excitations. The low-frequency optical conductivity has rather low value and shows quite small Drude-like response, indicating low carriers density in this material. Furthermore, the phonon modes increase continuously in frequency with decreasing temperature; specifically, the phonon mode around 200 cm$^{-1}$ shows an enhanced asymmetry effect at low temperatures, suggesting an increasing electron-phonon coupling in this system.

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B. Xu, Y. M. Dai, J. Han, K. Wang, R. Yang, Y. X. Yang, W. Zhang, H. Xiao, X. G. Qiu. 2014-05-27. Electron-phonon coupling in the superconducting single crystal Rb$_{0.8}$Fe$_{1.68}$Se$_2$. https://doi.org/10.1016/j.physc.2014.05.004

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