Strongly Correlated Electron Materials: Concepts and Applications

When: Thursday, April 26, 2012 at 4:00 pm
Where: DA 114
Speaker: Professor Gabriel Kotliar
Organization: Department of Physics and Astronomy, Rutgers University
Sponsor: Physics Colloquium

In the twentieth century, a “standard model” of solids was established.  It has successfully provided qualitative and quantitative guidance in describing the physical properties of many materials and holds great promise in guiding the search for new materials. Correlated electron systems are outliers whose behaviors do not fit within the standard model. They display remarkable phenomena ranging from high temperature superconductivity to metal to insulator transitions, sometimes accompanied by volume collapse. They continue to surprise us with their exceptional physical properties and the possibilities for new applications.

The discovery of interesting strongly correlated compounds so far has been the result of serendipity and the application of the Edisonian approach, the most recent example provided by iron arsenide superconductors.  From a theoretical perspective correlated electron systems are close to a localization-delocalization boundary. In this regime neither band theory (itinerant picture) nor atomic physics (localized picture) describes the physical properties of the materials posing one of the most difficult non-perturbative problems in physics.

In the past two decades we achieved significant progress in the description of the electronic structure of correlated materials through the development of the dynamical mean field theory (DMFT) approach. In this lecture we will give an elementary introduction to the field of strongly correlated electron systems and to the ideas of Dynamical Mean Field Theory (DMFT). We will illustrate the methodology with some examples drawn from f and d electron systems. We will conclude with an outlook of the challenges ahead and the prospect for theory assisted material design in correlated electron systems.