Periodic hole structure in a spin-chain ladder material Sr14Cu24O41 -: art. no. 012104

High-energy synchrotron x-ray diffraction measurements were carried out on a single crystal of Sr14Cu24O41, which had been reported to have different magnetic and structural correlations, in order to investigate the origin of this discrepancy more precisely. At low temperature, we observed weak superlattice peaks at Q=(0,0,2n+/-1/5)(c), while nothing was found at Q=(0,0,2n+/-1/4)(c), which was reported in a previous x-ray work by Cox [Phys. Rev. B 57, 10750 (1998)]. Therefore, the lattice distortion has not 4 but 5 times the periodicity of the chain structure along c (parallel to chain axis) direction. These satellite peaks decreased in intensity with increasing temperature. These observations were interpreted properly in terms of a hole ordering model involving the dimerized state of two Cu2+ ions and a Cu3+ ion on a Zhang-Rice singlet site in the CuO2 chains. These features were clearly observed by using high-energy x rays (E(i)similar or equal to53.789 keV), while the superlattice peak intensity varied drastically with very little sample surface treatment in the case of low-energy x-ray experiments (E(i)similar or equal to15.498 keV).