THz absorption bands in Sr14Cu24O41 by synchrotron radiation
We use unpolarized synchrotron radiation to probe the temperature dependent transmittance of single crystal Sr14Cu24O41 in the spectral range 15-110 cm-1 (0.45-3.3 THz). At high temperature we identify a conductivity band, which we assign to hole hopping between neighboring chains. At low temperatures we identify 14 resonance bands, 11 of which are previously unreported. Analysis of the absorption band spectral weight indicates mode coupling accompanying a transition in the vicinity of 100-200 K.