The origin of the superstructure in Bi₂Sr₂CaCu ₂O_8+δ as revealed by scanning tunneling microscopy

Real-space images with atomic resolution of the BiO plane of Bi 2Sr2CaCu2O8+δ were obtained with a scanning tunneling microscope. Single-crystal samples were cleaved and imaged under ultrahigh vacuum conditions at room temperature. The images clearly show the one-dimensional incommensurate superstructure along the b-axis that is common to this phase. High-resolution images show the position of the Bi atoms, revealing the structural nature of the superlattice. A missing row of Bi atoms occurs either every nine or ten atomic sites in both 〈110〉 directions, accounting for the measured incommensurate periodicity of the superstructure. A model is proposed that includes missing rows of atoms, as well as displacements of the atomic positions along both the a- and c-axis directions.

Duke Scholars

Author David Mitzi Thomas Lord Department of Mechanical Engineering and Materia ...