Charge-density analysis of YBa2Cu3O6.98. Comparison of theoretical and experimental results.

Using high-energy synchrotron radiation, structure factors of YBa(2)Cu(3)O(6.98) were measured at $\lambda$ = 0.124 A. Charge densities were derived using generalized structure factors and VALRAY and compared to densities refined from theoretical structure factors, which were calculated using the LAPW method and WIEN2k. Refinement agreement indices were R(F) = 0.0047 for the experimental and 0.0023 for the theoretical data set, respectively. Experimental and theoretical results generally agree well. A topological analysis shows that the structure is mainly ionic but depletion of charge density between Cu and O gives hints for covalency and confirms the general consensus of hole localization in these bonds.