Development of a functional renormalization group to treat interaction effects in strongly disordered electron systems

• Applicant: Professor Dr. Ferdinand Evers
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 198431769

Analytical treatments of interacting and disordered electron systems employ a perturbation theory assuming simultaneously weak disorder and weak interactions. Quite generally, these approaches break down near critical points, in particular near metal-insulator transitions, where the conductivity becomes small and the disorder no longer can be considered weak. Therefore, such methods cannot give unambiguous information about interaction effects in electron systems at or near the localization threshold. We start a longer term activity exploring a novel numerical technique along the lines of the functional renormalization group. The approach is perturbative in the interaction but (numerically) exact in the disorder. The goal is to study interaction effects on important localization transitions, including the integer quantum Hall transition and a newly predicted, self organized transition in the graphene material.

• DFG Programme: Research Grants