Impurity atoms on view in cuprates

The atomic-scale effects of individual Ni and Zn impurity atoms on the cuprate high critical temperature superconductors are analyzed using scanning t unnelling microscopy (STM). The low temperature STM can simultaneously image the surface topography and measure the local density of electronic states (LDOS). The atoms are displaced from their ideal orthrohombic lattice sites, forming a three-dimensional (3D) supermodulation⁹ of wavelength∼26 Å along the b-axis. It is found that a single impurity atom, substituted for Cu in the CuO₂ plane, disrupts the electronic environment and the electronic correlations between electrons on neighbouring Cu atoms.