9307328 Ng This project will investigate high-Tc materials using low temperature scanning tunneling microscopy. A ultra-high-vacuum system has been built to allow a study of tunneling as a function of angle with respect to the superconductor surface. In this way the anisotropy in the tunneling current will be sought. This can be related to anisotropy in the density of electronic states of the high-Tc materials, and provides input to and tests of current theories of high-Tc materials. The measurements will determine how the anisotropy is influenced by temperature variation, scattering processes, and the coupling strength between CuO2 layers. %%% This project studies the arrangement of electrons in the high-Tc superconducting materials. The high-Tc materials are characterized by planes composed of copper and oxygen atoms. Within these CuO2 planes, the arrangement of electron charge is anisotropic, but direct measurements to determine the anisotropy are very difficult. This project will use tunneling microscopy to detect electrons having the surface at various angles. The resulting anisotropy will be used to test current theories and will provide important fundamental information about the high-Tc materials. The information is also relevant to potential technology in that superconducting devices may depend on the anisotropic properties of the high-Tc materials. ***
