Control of electron-electron interaction in graphene by proximity screening

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 electronelectron 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.

Hot carriers in graphene – fundamentals and applications

“… 61 Furthermore, one can control carrier–carrier scattering by proximity screening, as demonstrated recently using a high-quality graphene sample with a nearby metal. 62 Finally, the application of a magnetic field will lead to less efficient carrier–carrier scattering. 63 …”

Precision measurement of electron-electron scattering in GaAs/AlGaAs using transverse magnetic focusing

“…We surmise that the nonuniversal prefactor originates in device-dependent electrostatic environments for the 2DES. While all three devices are fabricated on nominally the same heterostructure, the 3D electrostatic environment of the 2DES can vary between devices due to residual charged impurities, leading to varying levels of dielectric screening 39 . We then expect to possess a nonuniversal prefactor dependent on the screening strength 39 , affecting the magnitude of but not the dependence T −2 .…”

“…( 5 ) using the random phase approximation (RPA), dielectric screening is not included, as noted in ref. 39 . Varying levels of dielectric screening and concomitantly varying 3D electrostatic environments hence explain the nonuniversal prefactor of as well as the deviation of Eq.…”

Remote free-carrier screening to boost the mobility of Fröhlich-limited two-dimensional semiconductors

“…Encapsulating 2D materials in boron nitride (BN), for example, has already proven to be highly beneficial to the quality and cleanliness of the operating material's response [3,4]. The exciting prospect of including supporting 2D layers, to engineer the properties of the operating material beyond its intrinsic limits, has been much discussed in the past decade [5,6] but is only starting to be realized [7][8][9][10]. With this aim, one must understand, control, and exploit the interactions between all the layers within a VdWh.…”

“…In particular, we propose a GaSe/BN/graphene heterostructure, with doped graphene as a "screener" layer and BN as a separator. The principle of proximity free-carrier screening has recently been used to tune the band gap of semiconductors [21] and to manipulate electron-electron interactions in graphene [10]. We use it here to engineer electron-phonon interactions within the currentcarrying 2D semiconductor.…”