Theory of Metal-Insulator Transitions in Strongly Correlated Electronic Systems with Disorder

Florida State University, Tallahassee FL

Investigators

Abstract

0234215 Dobrosavljevic This award supports theoretical and computational research and education on the metal-insulator transition. Several different, but equally important, physical process all play a role; these include the physics of Anderson localization, the effects of strong correlations, and processes associated with glassy freezing of electrons. Energy scales associated with each of these processes are all comparable, so a successful theory must include them all on the same footing. All three basic physical processes associated with the metal-insulator transition can be consistently incorporated within extended dynamical mean-field theory (DMFT) approaches. They are all treated on the same, non-perturbative level allowing a realistic description of many materials. The PI aims to apply extended DMFT methods to several specific systems in an effort to explain phenomena that were beyond the reach of theoretical approaches in the past. Specific topics to be addressed include: (1) Disorder, magnetic field, and doping dependence of the critical behavior in doped semiconductors; (2) Localization effects on magnetic ordering in diluted magnetic semiconductors; (3) The two-dimensional metal-insulator transition viewed as a transition to a Mott-Anderson glass; (4) Non-equilibrium glassy dynamics of electron transport close to metal-insulator transitions; (5) Low temperature spin-glass behavior in electronic Griffiths phases of disordered heavy fermion compounds. In each of these projects, DMFT methods used will be technically tractable and will address the main physical questions. This award supports the integration of research at the forefront of condensed matter science and education at all academic levels: K-12, undergraduate, and graduate. This will be accomplished through participation in various activities, including: Outreach programs - The PI will contribute to enhancing scientific and technological understanding by communicating the importance of his research to the general public through various outreach activities, including lecturing at elementary schools, judging at annual regional Science Fairs, and participating in the FSU Physics Department Open House (PDOP) and the NHMFL Annual Open House activities. Research Experiences for Undergraduates (REU) program - The PI will participate in the REU Site at the NHMFL and plans to provide an opportunity for at least one intern every year to spend two summer months working on one of his research projects. FSU graduate students will be trained - The PI will supervise the research of several physics graduate students in physics. %%% This award supports theoretical and computational research and education on the transition between metallic and insulating states observed in two-dimensional systems, dilute magnetic semiconductors, and some heavy fermion materials. This problem is theoretically challenging in part because it involves different and possibly competing physical processes. The PI will apply and advance a promising avenue of inquiry based on the dynamical mean field theory and its extensions. This award also supports the PI's involvement in a range of education related activities including outreach, undergraduate involvement in the PI's research, and the training of the next generation of condensed matter theorists. ***