  It is now well established that superconductivity in cuprates competes with
charge modulations giving electronic phase separation at a nanoscale. More
specifically, superconducting electronic current takes root in the available
free space left by electronic charge ordered domains, called charge density
wave (CDW) puddles. This means that CDW domain arrangement plays a fundamental
role in the mechanism of high temperature superconductivity in cuprates. Here
we report about the possibility of controlling the population and spatial
organization of the charge density wave puddles in a single crystal La2CuO4+y
through X - ray illumination and thermal treatments. We apply a pump - probe
method based on X - ray illumination as pump and X - ray diffraction as a probe
setting a writing and reading procedure of CDW puddles. Our findings are
expected to allow new routes for advanced design and manipulation of
superconducting pathways in new electronics.
