This CAREER award supports theoretical research and education to investigate recently discovered materials and materials-related effects involving strongly correlated electrons and spin dynamics. The research has four main thrusts:
1) Iron-based oxypnictide superconductors. The PI's study will have particular emphasis on the mechanism responsible for their high-temperature superconductivity, the pairing symmetry, possible new collective modes in the superconducting state, development of new techniques beyond one-loop functional renormalization group to deal with strongly correlated systems, and experimentally testable predictions of different weak and strong-coupling theories. The PI will also focus some effort on issues in cuprate superconductors such as investigation of Gutzwiller-projected wavefunctions.
2) Non-abelian fractional quantum Hall states and non-abelian fractional statistics. The research will focus on understanding the imprint of topological order and pushing the boundaries of numerical computation for these truly strongly-interacting systems through new and insightful approximations.
3) Topological insulators and the quantum spin Hall effect. The research will have emphasis on the prediction of new materials exhibiting this effect, the physics of the gapless edge and surface states at low-temperature, experimentally falsifiable predictions about the bulk physics of these materials when doped and subjected to magnetic and electric fields, and novel transport laws that they might exhibit. The PI will also look into the possibility of using these materials in specific thermoelectric devices.
4) The effects of spin-charge dynamics in systems with strong spin-orbit coupling in both the diffusive and ballistic regimes, and the study of new spin-relaxation mechanisms, such as random spin-orbit coupling.
The educational activities associated with this CAREER award include several initiatives geared toward making substantial contributions to undergraduate and graduate education through pedagogical course development coupled with research seminars, outreach activities in the form of lecture series and one-semester courses designed for non-science students and the general public, as well as fostering interactions between academia and industry. Some of these initiatives will leverage resources of the Princeton Center for Theoretical Science to uniquely maximize the impact of the planned educational activities.
NON-TECHNICAL SUMMARY
This CAREER award supports theoretical research and education on new materials with interesting and exciting properties, and intriguing new effects. These include iron-based superconductors and topological insulators. Superconducting materials can conduct electricity without losses when they are cooled to sufficiently low temperature which is well below room temperature. The iron-based superconductors are interesting because they remain superconducting to higher temperatures than many other known materials. Understanding these materials may hold the key to achieving superconductivity at room temperature. The PI aims to understand how electrons in these materials organize themselves into high temperature superconducting states.
The PI will also use theoretical methods to search for new materials that are topological insulators. Like ordinary insulators, for example rubber, topological insulators do not conduct electricity though the interior of the material. Unlike ordinary insulators, topological insulators are able to conduct electricity on their edges or boundaries through the formation of a new state of matter. Among the known topological insulators are compounds made of the elements bismuth and selenium, and bismuth and tellurium.
This award supports fundamental research that advances our fundamental understanding of how electrons organize themselves into new states of matter which exist in or on the surface of materials. Their existence is in part a consequence of properties of the materials. While interesting in their own right, the study of these new states of matter may lead to foundations for new device technologies. Research successes leading to the discovery of new high temperature superconductor materials may lead to significant energy savings by enabling low loss energy transmission. The PI will interact closely with several experimental groups working on these problems to ensure that the research will benefit the overall progress of the fields indicated.
The educational activities associated with this CAREER award include several initiatives geared toward making substantial contributions to undergraduate and graduate education through pedagogical course development coupled with research seminars, outreach activities in the form of lecture series and one-semester courses designed for non-science students and the general public, as well as fostering interactions between academia and industry. Some of these initiatives will leverage resources of the Princeton Center for Theoretical Science to uniquely maximize the impact of the planned educational activities.
