Plasmonic Superconductivity in Layered Materials

Due to a lack of screening in two dimensions the Coulomb interaction is generally enhanced and consequently plays a major role to understand many-body effects within layered materials. In the field of superconductivity it is usually introduced as an approximate, static, and adjustable parameter µ^* which describes only effectively the Coulomb repulsion.
Here, we overcome this inadequate handling and present an ab initio based material-realistic Coulomb description for a doped 2D system which captures simultaneously material-intrinsic, substrate, and dynamical screening processes. We show that by changing the doping level or dielectric environment it is possible to precisely tune the electron-plasmon interaction. We use SC-DFT to calculate the superconducting critical temperature and show that by tuning the plasmon dispersion one can tune the superconducting state. We see enhancement of the critical temperature by up to a factor of 5 (compared to the standard phonon case) for some doping / dielectric combinations while there is a decrease of the critical temperature for other situations. We discuss the subtle interplay of different factors to explain the calculated results.