Condensed Matter Seminar

Gianluigi Catelani
Cornell University

Thursday, April 27, 2006
1:00 pm in SPL 52

Interaction corrections to transport in disordered metals:
quantum kinetic equation and the Wiedemann-Franz law

Abstract: The Wiedemann-Franz law relating electrical and thermal conductivities is usually regarded as a signature of Fermi-liquid theory; however it strictly holds only when transport phenomena are determined by elastic scattering processes whose cross section smoothly depends on the energy. Moreover it is well known that at low temperatures singular corrections to the electrical conductivity arise because of the electron-electron interactions. The question I will address is whether the Wiedemann-Franz law is still valid if one accounts for the interaction effects. I will show that there are deviations from this law which include but are not limited to those due to the energy dependence of the scattering rate. In particular, a large contribution to the violation of the Wiedemann-Franz law comes from the energy transported by neutral bosonic excitations: these low-energy modes must be introduced in order to obtain a local kinetic description of the interacting disordered metal.