Spatial and Temporal Complexity in Disordered Strongly Correlated Electronic Systems

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TECHNICAL SUMMARY:Novel materials with strong electronic correlations can lead to spontaneous electronic pattern formation and complexity at the nanoscale. Understanding the formation of these patterns may be a key to our understanding of the macroscopic electronic properties and to our eventual technological control of these materials. The PI will use techniques from disordered and glassy systems to determine the fundamental physics governing the nanoscale pattern formation. Broader impacts include mentoring graduate women in physics, outreach to high schools, and the training of graduate students. While there is growing consensus that many strongly correlated electronic systems are highly susceptible to pattern formation at the nanoscale, unfortunately most of our theoretical and experimental tools are designed for understanding and detecting homogeneous phases of matter. The PI will design and develop new ways of understanding, detecting, and characterizing electronic pattern formation in strongly correlated electronic systems at the nanoscale, especially in the presence of strong disorder effects. The PI will employ techniques from the study of glasses and disordered phases both in and out of equilibrium with the aim to determine the fundamental physics governing the nanoscale pattern formation, as well as how the macroscopic behavior that arises from novel nanoscale structure. A goal of the research is that several conventional and widely available experimental techniques will include new modes of the way data is acquired and its analysis and new theoretical tools that enable the detection and characterization of novel phases of matter.The PI will continue to develop the mentoring program she began for graduate women in the physics program at her home institution. The PI will visit local high schools to discuss her research. This outreach combines interactive hands-on superconductivity demonstrations with education about current condensed matter research. In addition, the proposed work will advance the training of one graduate student. NONTECHNICAL SUMMARY:This award supports theoretical research and education on the complex pattern formation which has been observed to occur among the electrons in an interesting class of materials that include high-temperature superconductors and colossal magnetoresistance materials. Useful conceptualizations of electronic states in many materials are often based on the idea that electronic states inside the material are uniform. The electronic states in ordinary metal wires, in semiconductors and in some magnets are examples. High temperature superconductors have emerged as examples that break this paradigm in a new way. The electrons themselves form intricate patterns inside the materials. This kind of clumpy behavior among the electrons may hold the key to some of the exotic properties which have been observed in the larger class of strongly correlated materials. The name reflects the role of strong interactions among electrons leading to correlations in their motions. Of specific interest to the PI are technologically important properties such as high temperature superconductivity, which may have impact on technologies to increase energy efficiency, and colossal magnetoresistance materials which exhibit an amazingly large change in resistance to electric current flow when placed in a magnetic field. Some examples of this pattern formation are also fractal in character, meaning that the patterns simultaneously incorporate similar structural details at small, medium, and large length scales.Current theoretical and experimental techniques are inadequate for detecting or classifying the clumpy behavior of the electrons inside these materials. The PI will design and develop new ways of understanding, detecting, and characterizing electronic pattern formation in these strongly correlated materials on the length scales of atoms and molecules. In order to accomplish this, the PI will use techniques from the study of glasses such as window glass and other disordered materials with an aim to determine the fundamental physics responsible for the complex pattern formation of the electrons inside these materials. A possible outcome of this research is that several conventional and widely available experimental techniques will have at their disposal new modes of data acquisition and analysis and new concepts that will enable the detection and characterization of new inhomogeneous phases of matter. This project also supports training one graduate student, mentoring graduate women in physics, and outreach to local high schools which combines interactive hands-on superconductivity demonstrations with education about the PI's current research in condensed matter physics.