Spatial inhomogeneity and chiral symmetry of the lattice incommensurate   supermodulation in high temperature superconductor Bi2Sr2CaCu2O8+y
  Using scanning micro X-ray diffraction we report a mixed real and reciprocal space visualization of the spatial heterogeneity of the lattice incommensurate supermodulation in single crystal of Bi2Sr2CaCu2O8+y with Tc=84 K. The mapping shows an amplitude distribution of the supermodulation with large lattice fluctuations at microscale with about 50% amplitude variation. The angular distribution of the supermodulation amplitude in the a-b plane shows a lattice chiral symmetry, forming a left-handed oriented striped pattern. The spatial correlation of the supermodulation is well described by a compressed exponential with an exponent of 1.5 and a correlation length of about 50 {\mu}m, showing the intrinsic lattice disorder in high temperature superconductors. 
Nicola Poccia, Gaetano Campi, Michela Fratini, Alessandro Ricci,   Naurang L. Saini, Antonio Bianconi
cond-mat.supr-con