This CAREER award supports theoretical research and education focused on the response of electrons in nanoscale structures to external fields, such as electric fields. These systems are out of thermodynamic equilibrium and the propagation of electrons is very sensitive to external fields. The PI will pursue a theoretical description based on the quantum kinetic equation combined with diagrammatic and semiclassical methods and focus on the electronic properties of metallic nanoparticles and nanowires, and lateral electron quantum dots which are governed by a complicated interplay between quantum electron propagation and interaction-induced relaxations. The PI will analyze the role of Coulomb, magnetic, and superconducting pairing interactions between electrons in determining transport and thermodynamic properties of nanoscale conductors. Of particular interest are the instabilities due to magnetic and superconducting interactions. In equilibrium bulk systems these instabilities are known to result in phase transitions. The PI will look for manifestations of these instabilities in out-of-equilibrium nanoscale systems and their effects on non-linear transport and noise characteristics of these systems. The PI will also investigate transport in conventional superconductors with a subsystem of interacting magnetic impurities. High mobility two-dimensional electron systems, existing in semiconductor heterostructures, also show a wide variety of non-linear phenomena in moderate magnetic fields, such as microwave-induced magnetooscillations and oscillatory differential dc resistance. The results of experimental studies of high mobility two dimensional electron gases have been puzzling and further investigation is needed, including an analysis of electron-electron and electron-phonon interactions. Two-dimensional systems with more complicated band structure will be investigated as well. The education component involves developing a special lecture course and a research opportunity for students aimed at enabling them to learn modern theoretical methods and to work independently on cutting edge research projects following their graduation. It also includes an outreach component that will aim to explain the modern challenges of condensed matter physics arising on nanometer length-scales to high school students and members of the local community. The PI will proactively engage members of underrepresented groups in research and learning. The PI will also actively participate in existing local outreach programs aimed at enhancing public awareness of progress, promises and benefits to society of materials sciences and nanotechnology.
NONTECHNICAL SUMMARY This CAREER award supports theoretical research and education focused on metallic structures of atoms and molecules that have dimensions on the scale of nanometers. For reference, a human hair is about a hundred thousand times larger. The electrons contained in these tiny nanostructures require a quantum mechanical description that includes their wave-like properties. This research project is focused on how the electrons in nanostructures respond to external fields, like an electric field that one might associate with conventional electric power source. Recent experiments have shown that interesting new phenomena can arise. A focus of this research is the discovery of new phenomena as well as contributing to the understanding of experiments on wire-like nanostructures and nanostructures that are little more than one or an assembly of dots. Some macroscopic materials become magnets or may display other electronic states of matter. These arise as a consequence of interactions among electrons. The PI is particularly interested in discovering analogs of these states that arise in nanostructures where the electrons are exposed to fields.
This is fundamental research that contributes to the discovery of new phenomena and new states of matter on the nanoscale which can lead to new electronic device technologies in the quest to sustain increasing performance and decreasing size of electronic devices that have characterized the rise of modern computers.
The education component involves developing a special lecture course and a research opportunity for students aimed at enabling them to learn modern theoretical methods and to work independently on cutting edge research projects following their graduation. It also includes an outreach component that will aim to explain the modern challenges of condensed matter physics arising on nanometer length-scales to high school students and members of the local community. The PI will proactively engage members of underrepresented groups in research and learning. The PI will also actively participate in existing local outreach programs aimed at enhancing public awareness of progress, promises and benefits to society of materials sciences and nanotechnology.
