****Technical Abstract**** This project will involve low temperature experiments that elucidate properties of a state of matter exhibiting both superconductor and insulator characteristics simultaneously. It builds on substantial progress showing that this Cooper pair insulator state has a spatially inhomogeneous granular structure that emerges spontaneously. This quality appears commonly among many other interesting systems in which electron correlations effects are strong. Experiments will focus on the Cooper pair insulator phase in thin amorphous films deposited on the surfaces of nano-porous anodized aluminum oxide substrates. Investigations of how this phase responds to magnetic impurity doping, depends on the physical dimensions of the films and evolves with systematic changes in the substrate nano-structure will be conducted. These results can reveal the factors driving the Cooper pair localization and the size of the localized states. These studies will be the platform for training graduate and undergraduate students in nano-technology and forefront issues relevant to the development of new materials for applications. This type of training has been good preparation for careers in industry. The results will impact the general field of condensed matter electronics by providing new insights into how granularity emerges and the properties of correlated electron systems.
This award supports experimental research in condensed matter physics that will be performed with PhD and undergraduate students. The investigations focus specifically on a class of materials that has been transformed dramatically using nano-technology. The material normally superconducts (i.e. carries electricity without losing energy) but becomes an exceptional electrical non-conductor or insulator when patterned with nano-technology. The experiments build on recent work showing that these insulators consist of electrically disconnected grains of superconductor that are few billionths of a meter in size. The experiments will study the factors that drive the spontaneous formation of these grains. These insights will be valuable for understanding the electrical properties of many other recently discovered materials that show similar spontaneous grain formation as well as promise in future applications. This research program will expose the PhD and undergraduate students to scientific issues relevant to the development of new materials for high technology. This type of training has been excellent for launching the careers of scientists in high technology fields.
