A superstructure in single-crystal YBa2Cu3O7-δ

Abstract
A new form of superstructure with a square root 2*2 square root 2*1 supercell oriented at 45 degrees to the original unit-cell axes has been found in a YBa2Cu3O7- delta single crystals by means of electron diffraction and electron microscopy. It is suggested that this superstructure results from a substructure modulation.