  Using first-principles calculations based on density functional theory and
non-equilibrium Green's functions, we characterized the effect of surface
termination on the electronic transport properties of nanoscale Cu slabs. With
ideal, clean (111) surfaces and oxidized ones as baselines we explore the
effect of capping the slabs with graphene, hexagonal boron nitrate, molybdenum
disulfide and stanene. Surface oxide suppresses balistic conductance by a
factor of 10 compared to the ideal surface. Capping the ideal copper surface
with graphene slightly increase conductance but MoS$_2$ and stanene have the
opposite effect due to stronger interactions at the interface. Interestingly,
we find that capping atomistically roughed copper surfaces with graphene or
MoS$_2$ decreases the resistance per unit length by 20 and 13%, respectively,
due to reduced scattering. The results presented in this work suggest that
two-dimensional materials can be used as an ultra-thin liner in metallic
interconnect technology without increasing the interconnect line resistivity
significantly.
