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Collective density wave excitations in two-leg Sr_{14-x}Ca_xCu_{24}O_{41} ladders

A. Gozar·G. Blumberg·P. B. Littlewood·B. S. Dennis·N. Motoyama·H. Eisaki·S. Uchida
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Abstract

Raman measurements in the 1.5 - 20 cm-1 energy range were performed on single crystals of Sr_{14-x}Ca_xCu_{24}O_{41}. A quasielastic scattering peak (QEP) which softens with cooling is observed in the polarization parallel to the ladder direction for samples with x = 0, 8 and 12. The QEP is a Raman fingerprint of pinned collective density wave excitations screened by uncondensed carriers. Our results suggest that transport in metallic samples, which is similar to transport in underdoped high-T_c cuprates, is driven by a collective electronic response.

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A. Gozar, G. Blumberg, P. B. Littlewood, B. S. Dennis, N. Motoyama, H. Eisaki, S. Uchida. 2002-07-09. Collective density wave excitations in two-leg Sr_{14-x}Ca_xCu_{24}O_{41} ladders. https://doi.org/10.1103/physrevlett.91.087401

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