Control of electron-electron interaction in graphene by proximity screening
Minsoo Kim, Shuigang Xu, Alexey I. Berdyugin, Alessandro Principi, Sergey Slizovskiy, Na Xin, Piranavan Kumaravadivel, Wenjun Kuang, Matthew J. Hamer, Roshan Krishna Kumar, Roman Gorbachev, Kenji Watanabe, Takashi Taniguchi, I. V. Grigorieva, Vladimir I. Fal’ko, Marco Polini, A. K. Geǐm
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.