****Technical Abstract**** Within the field of condensed matter physics, our understanding of disordered systems lags far behind our understanding of crystalline ones. In crystalline systems, defects are known to control mechanical fragility, but there are no obvious counterparts to defects in disordered solids. This experimental program explores the source of mechanical fragility in disordered solids by using a recently developed laser-poking technique to perturb disordered colloidal solids and track induced particle rearrangements using video microscopy. Critical to this project is employing a new data analysis approach that has been shown to greatly reduce the complexity of disordered solids, perhaps even identifying structurally weak regions. The results from this project will be a great interest to both the scientific and engineering communities as our current limited understanding of disordered materials impedes the progress in both modeling materials as well as designing new materials with improved mechanical properties. Beyond addressing an important and open question in the field of condensed matter physics, the project will also provide critical experience to undergraduate researchers who will conduct the research and broadly disseminate the results through student-coauthored papers as well as talks at national conferences. Furthermore, the proposed research will offer opportunities to student researchers from a diverse range of backgrounds found at a state institution and encourage them towards careers in science and technology.
This experimental program explores the mechanical properties of amorphous solids. In contrast to crystalline solids, amorphous solids have a disordered atomic structure. Because of this complexity, physicists lack a clear physical picture of how the structure of disordered solids relates to their mechanical properties. This limited understanding of disordered materials has hindered the application of such materials as bulk metallic glasses, amorphous thin films, and nanoparticles assemblies. Using a recently developed laser-poking technique, this project will explore the mechanical response of colloidal disordered solids to stress. The experimental results from this research will serve to validate or disprove current theories relating to amorphous solids, aid in the development of a clear physical picture of amorphous solids, and provide a framework to support the development of new materials as well as improve the design of current ones. Beyond addressing an important and open question in the field of condensed matter physics, this project will also provide critical experience to undergraduate researchers who will conduct the research and broadly disseminate the results through student-coauthored papers as well as talks at national conferences. Furthermore, the proposed research will offer opportunities to student researchers from a diverse range of backgrounds found at a state institution and encourage them towards careers in science and technology.
