This award will support collaborative research between Prof. Christopher Lobb of Harvard University and Dr. Miguel Octavio of the Instituto Venezolano de Investigaciones Cientificas (IVIC) in Caracas, Venezuela. The objective of the research is to continue present work concerned with theoretical and experimental aspects of percolation theory and superconductivity in random media. Percolation theory serves to unite several seemingly diverse phenomena such as fluid flow in porous media, the strength of composites and ceramics, dielectric breakdown in granular materials, and the electrical properties of superconducting composite wires. Recent theoretical advances have led to an increased understanding of percolation in real materials with generally good agreement between theory and simulations. Work remains to be done in comparing theoretical predictions to measurements on real systems. The researchers intend to perform theoretical work at Harvard, and computer simulations at IVIC. Two types of experiments are currently undertaken and will be continued: at IVIC thin percolative films are being grown and studied in situ, aiming at understanding thin film growth and its effect on superconductivity. At Harvard, artificial random films are being made using electron-beam lithography. Complementary facilities will allow a wide range of experiments to be done. This research has the potential for broad applicability from a fundamental science point of view--the study of transport and breakdown processes in random media--to technological applications such as the strength of composite materials.
