• Control of electron-electron interaction in graphene by proximity screening

      Kim, M.; orcid: 0000-0001-6304-6901; Xu, S. G.; orcid: 0000-0002-0589-5291; Berdyugin, A. I.; Principi, A.; Slizovskiy, S.; Xin, N.; Kumaravadivel, P.; orcid: 0000-0002-9817-1697; Kuang, W.; orcid: 0000-0003-4309-365X; Hamer, M.; Krishna Kumar, R.; et al. (Nature Publishing Group UK, 2020-05-11)
      Abstract: Electron-electron interactions play a critical role in many condensed matter phenomena, and it is tempting to find a way to control them by changing the interactions’ strength. One possible approach is to place a studied system in proximity of a metal, which induces additional screening and hence suppresses electron interactions. Here, using devices with atomically-thin gate dielectrics and atomically-flat metallic gates, we measure the electron-electron scattering length in graphene and report qualitative deviations from the standard behavior. The changes induced by screening become important only at gate dielectric thicknesses of a few nm, much smaller than a typical separation between electrons. Our theoretical analysis agrees well with the scattering rates extracted from measurements of electron viscosity in monolayer graphene and of umklapp electron-electron scattering in graphene superlattices. The results provide a guidance for future attempts to achieve proximity screening of many-body phenomena in two-dimensional systems.