Monday, November 09, 20153:00 PM - 4:00 PMCNLS Conference Room (TA-3, Bldg 1690)|
Superconductivity from repulsive interactions
Andrey ChubukovDepartment of Physics, University of Minnesota
In BCS theory of superconductivity, electron-phonon interaction is a glue that overcomes Coulomb repulsion and binds fermions into pairs which then condense and super-conduct. In my talk, I review recent and not so recent works aiming to understand whether a nominally repulsive Coulomb interaction can by itself give rise to a superconductivity. I first discuss a generic scenario of the pairing by electron-electron interaction, put forward by Kohn and Luttinger back in 1965, and then discuss modern studies of the electronic mechanisms of superconductivity in the lattice systems which model cuprates, Fe-pnictides, and doped graphene. I show that the pairing in all three classes of materials can be viewed as lattice version of Kohn-Luttinger physics, despite that the pairing symmetries are different. I discuss under what conditions the pairing occurs and rationalize the need to do parquet renormalization-group studies. I also analyze the interplay between superconductivity and density-wave instabilities.
Host: Angel E. Garcia