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Microwave and millimeter wave spectroscopy in the slightly hole-doped ladders of Sr$_{14}$Cu$_{24}$O$_{41}$

H. Kitano·R. Inoue·T. Hanaguri·A. Maeda·N. Motoyama·M. Takaba·K. Kojima·H. Eisaki·S. Uchida
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Abstract

We have measured the temperature- and frequency dependence of the microwave and millimeter wave conductivity $σ_1(T,ω)$ along both the ladder (c-axis) and the leg (a-axis) directions in Sr$_{14}$Cu$_{24}$O$_{41}$. Below a temperature $T^*$($\sim$170 K), we observed a stronger frequency dependence in $σ_1^c(T,ω)$ than that in $σ_1^a(T,ω)$, forming a small resonance peak developed between 30 GHz and 100 GHz. We also observed nonlinear dc conduction along the c-axis at rather low electric fields below $T^*$. These results suggest some collective excitation contributes to the c-axis charge dynamics of the slightly hole-doped ladders of Sr$_{14}$Cu$_{24}$O$_{41}$ below $T^*$.

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H. Kitano, R. Inoue, T. Hanaguri, A. Maeda, N. Motoyama, M. Takaba, K. Kojima, H. Eisaki, S. Uchida. 2001-08-14. Microwave and millimeter wave spectroscopy in the slightly hole-doped ladders of Sr$_{14}$Cu$_{24}$O$_{41}$. https://doi.org/10.1209/epl%2Fi2001-00537-2

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