A quantitative description of Coulomb interactions is developed for two-dimensional superconducting materials, enabling us to compare intrinsic with external screening effects, such as those due to substrates. Using the example of a doped monolayer of MoS2 embedded in a tunable dielectric environment, we demonstrate that the influence of external screening is limited to a length scale, bounded from below by the effective thickness of the quasi-two-dimensional material and from above by its intrinsic screening length. As a consequence, it is found that unconventional Coulomb-driven superconductivity cannot be induced in MoS2 by tuning the substrate properties alone. Our calculations of the retarded Morel-Anderson Coulomb potential {\mu *} reveal that the Coulomb interactions, renormalized by the reduced layer thickness and the substrate properties, can shift the onset of the electron-phonon driven superconducting phase in monolayer MoS2 but do not significantly affect the critical temperature at optimal doping.
@article{arxiv.1605.07489,
title = {Interplay of screening and superconductivity in low-dimensional materials},
author = {G. Schönhoff and M. Rösner and R. Groenewald and S. Haas and T. O. Wehling},
journal= {arXiv preprint arXiv:1605.07489},
year = {2016}
}