DMREF/Collaborative Research: Designing, Understanding and Functionalizing Novel Superconductors and Magnetic Derivatives

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NON-TECHNICAL SUMMARYThis DMREF project aims to make breakthroughs in understanding and designing novel superconductors, magnetic semiconductors, and other magnetic materials. The research can lead to development of materials with higher transition temperatures suitable for applications to electronic devices with novel functionalities. To achieve this goal, collaborative research will be performed by five Principal Investigators (PIs) specializing in a variety of techniques and methods, including neutron scattering (Dai) and muon spin relaxation (Uemura) as advanced magnetic probes, synthesis and charge transport of nano-scale systems (Ni and Kim), and theory and computational material design (Kotliar). The team members will unite their forces and expertise to characterize high-quality specimens with multiple experimental probes, to explore electric field-effect doping of charge carriers using nano-scale devices, to interpret the results using advanced computational models, and to design and synthesize new materials. As demonstrated in recent discoveries of ferromagnetic semiconductors that have crystal structures identical to those of Fe-based high-Tc superconductors, encounters and coherent collaboration between experts from different research communities will lead to unanticipated breakthroughs. Since 2011, the PIs from Columbia and Rice have organized live/video lecture courses for entry-level graduate students "Frontiers of Condensed Matter Physics" seeking broader impact, and have accumulated about 100 video lectures of leading scientists describing modern studies of solid state physics. The present project will allow adding a new series to this course involving faculty members from Columbia, Rice, Harvard, Rutgers, and UCLA and connecting their classrooms with a web-based technology for simultaneous broadcast. TECHNICAL SUMMARYCondensation and pairing mechanisms of high-Tc cuprate and iron-based superconductors have not yet been established. However, there are growing signatures pointing toward the important role played by magnetic interactions. With multi-probe experimental researchers using neutrons, muons, transport, and scanning tunneling microscopy (STM), supplemented by quantitative comparison to advanced computation, the present DMREF project will shed new light on the quest for understanding unconventional superconductors. In conjunction with the predictive powers of advanced computational methods, a better understanding of the physical mechanisms at work will contribute to the ability to design materials with higher transition temperatures. Carrier doping using electric field effects will provide a new route to search for novel superconductors, less sensitive to disorder effects associated with conventional doping with chemical substitutions. Transport results on Fermi-level tuning via electrolyte gate voltage will be directly compared to advanced theoretical computations on electronic structures. Additionally, the formation of interfaces of unconventional superconductors and their magnetic derivatives, and engineering of phase changes via charge-doping with field-effect gating, will result in devices with novel functionality, leading to an as yet unexplored interdisciplinary research front. This project will provide a unique collaborative experience involving leading researchers, graduate students, and postdocs with multiple research fields and techniques that will make important contributions to the development of the future leaders of modern physics research.