Thomas Lee Elifritz

Long-Range Incommensurate Charge Fluctuations in (Y,Nd)Ba₂Cu₃O_6+x, G. Ghiringhelli, M. Le Tacon, M. Minola, S. Blanco-Canosa, C. Mazzoli, N. B. Brookes, G. M. De Luca, A. Frano, D. G. Hawthorn, F. He, T. Loew, M. Moretti Sala, D. C. Peets, M. Salluzzo, E. Schierle, R. Sutarto, G. A. Sawatzky, E. Weschke, B. Keimer and L. Braicovich, Science, 12 June 2012.

http://www.sciencemag.org/content/early/2012/07/11/science.1223532

We have used resonant soft x-ray scattering to identify two-dimensional charge fluctuations with an incommensurate periodicity of ~3.2 lattice units, a, in the copper-oxide planes of the superconductors (Y,Nd)Ba₂Cu₃O_6+x with hole concentrations 0.09 ≤ p ≤ 0.13 per planar Cu ion. The intensity and correlation length of the fluctuation signal increase strongly upon cooling down to the superconducting transition temperature, T_c; further cooling below T_c abruptly reverses the divergence of the charge correlations. In combination with prior observations of a large gap in the spin excitation spectrum, these data indicate an incipient charge-density-wave instability that competes with superconductivity.

lifeform@charter.net