Determination of the incommensurate modulated structure of Bi₂Sr_1.6La_0.4CuO_6+δ by aberration-corrected transmission electron microscopy

The incommensurate modulated structure (IMS) of Bi₂Sr_1.6La_0.4CuO_6+δ (BSLCO) has been studied by aberration-corrected transmission electron microscopy in combination with a high-dimensional (HD) space description. Two images are deconvoluted in the negative Cs imaging (NCSI) and positive Cs imaging (PCSI) modes. Similar results for the IMS have been obtained from two corresponding projected potential maps (PPMs), and the size of the dots representing atoms in the NCSI PPM is found to be smaller than that in the PCSI PPM. Considering that the object size is one of the factors that influence the precision of the structural determination, modulation functions for all unoverlapped atoms in BSLCO were determined on the basis of the NCSI PPM in combination with the HD space description.