Quantum critical transport in electronic systems and spin liquids

• Applicant: Dr. Lars Fritz
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2011 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 198775606

The subject of the project is the study of strongly correlated electronic systems with an emphasis on quantum critical points and critical phases. I intend to study specific aspects of strongly correlated electronic systems, namely transport in systems close to their critical point and spin order/dynamics in highly frustrated magnetic systems, which are possibly spin liquids. Concerning quantum critical transport, the main objectives are a description of non equilibrium transport and an understanding of the interplay of collective modes, disorder, and drag effects. In particular, I plan to study non equilibrium transport in graphene, whose discovery recently was rewarded with the Nobel prize. The interplay of collective modes, disorder, and drag effects will be studied independently in the framework of a generic spin density wave scenario. The insights of both investigations will be applied to describe experiments on thin films of critical ferromagnetic metals in the nonlinear transport regime. Highly frustrated magnetic systems, in particular certain higher dimensional versions of kagomé antiferromagnets, are currently investigated at the Universität zu Köln. These systems have recently been discovered and very little theoretical knowledge about them is available. A first goal is to find a minimal description of their magnetism. The long term objective is to determine whether the systems under investigation qualify as spin liquids. As an interesting perspective the knowledge about transport in correlated systems gained in the first part of the project can be used to investigate heat transport in those strongly correlated spins systems, which is one of the hallmark measurements in the field of spin liquids.

• DFG Programme: Independent Junior Research Groups
• International Connection: Netherlands