Speaker: Kristjan Haule, Center for Materials Theory Department of Physics & Astronomy
Date & Time: September 10, 2008 - 4:45pm
Location: Physics Lecture Hall
Predicting and Understanding Correlated Electron Materials: A Computational Approach
Physics and Astronomy
Kristjan Haule, Center for Materials Theory Department of Physics & Astronomy, Rutgers University
4:45 PM, Physics Lecture Hall
Materials with strong electronic correlations have long resisted abinitio modeling due to their complexity arising from non-perturbative strength of the interaction. The Dynamical Mean Field Theory in combination with the Density Functional Theory has recently changed this position, and enabled detailed modeling of the electronic structure of complex heavy fermions, transition metal oxides and arsenides. Many peculiar properties of heavy fermion materials with chemical formula CeTIn5, where T is Ir, Rh or Co, were understood within this approach, such as the slow buildup of coherence in the form of a dispersive many body feature, multiple peak structures observed in optical experiments, and the sensitivity of the substitutions of the transition metal ion. The new class of high temperature superconductors based on iron and arsenic were recently found and ended a few decades long domination of copper oxides in this fields. The incoherence of the normal state of these compound is in common to all strongly correlated superconductors, the mechanism for emergence of the incoherent state in iron-oxypnictides, is however unique due to its multiorbital electronic structure and the strength of the Hund's rule coupling.