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

Van der Waals heterostructures provide a versatile tool to not only protect or control, but also enhance the properties of 2D material. We use ab initio calculations and semi-analytical models find strategies which boost mobility current-carrying semiconductor within an heterostructure. Free-carrier screening from metallic "screener" layer remotely suppresses electron-phonon interactions in layer. This concept is most effective semiconductors whose scattering dominated by screenable interactions, particular Fr\"ohlich coupling polar-optical phonons. Such materials are common characterised overall low mobilities small doping limit, much higher ones when material doped enough for be screened its own free carriers. GaSe as prototype place it heterostructure with graphene BN separator. develop approach determine electrostatic response any combining responses individual layers computed density-functional perturbation theory. Remote can suppress long-wavelength interaction, leading consistently high around $500$ $600$ cm$^2$/Vs carrier densities $10^{11}$ $10^{13}$ cm$^{-2}$. Notably, low-doping enhanced factor 2.5. remote free-carrier more efficient than conventional manipulation dielectric environment, separator (BN) thin.