Johannes Lischner
Imperial College London
Abstract:
Twisted bilayer materials are an attractive emerging platform for studying electron correlations. For example, the phase diagram of twisted bilayer graphene contains correlated insulator states in the vicinity of superconducting domes and is thus reminiscent of the cuprate high-temperature superconductors. However, the two-dimensional nature of this system allows for new ways to study electron correlations which are not accessible in the cuprates. For example, it is possible to modify the effective interaction between electrons by device engineering, i.e. by changing the dielectric environment and controlling the distance to the metallic gates. In my talk, I will show how the screened interaction between electrons in twisted bilayer graphene depends on the dielectric environment and how this results in profound changes to the phase diagram. I will also discuss the role of internal screening which could potentially give rise to superconductivity mediated by a polarization glue.