LOW-TEMPERATURE CHARGE ORDERING IN SR14CU24O41

Synchrotron x-ray measurements were made between 20-300 K on single cr ystals of Sr14Cu24O41 which has a quasi-one-dimensional chain and ladd er structure, in order to investigate possible charge-ordering effects in the CuO2 chains as indicated by recent NMR studies. At 50 K a few very weak satellite peaks were observed at (00l) positions correspondi ng to a fourfold increase in periodicity along the chain axis. These p eaks decreased in intensity with increasing temperature, and eventuall y disappeared close to 300 K. The observations were interpreted in ter ms of a charge-ordered model involving both dimerization between two n ext-nearest-neighbor Cu2+ ions surrounding a Cu3+ ion on a Zhang-Rice singlet site, and dimerization between nearest-neighbor Cu2+ ions. [S0 163-1829(98)06617-X].