Coulomb Drag in Graphene/h-BN/Graphene Moire<acute accent> Heterostructures

We report on the observation of Coulomb drag between graphene-hexagonal boron nitride (h-BN) moire<acute accent> heterostructure with a moire<acute accent> wavelength of similar to 14 nm and an intrinsic graphene with a lattice constant of similar to 0.25 nm. By tuning carrier densities of each graphene layer independently, we find that charge carriers in moire<acute accent> minibands, i.e., near satellite Dirac point (sDP), can be coupled with massless Fermions near the original Dirac point (oDP), strongly enough to generate a finite drag resistivity. At high temperature (T) and large density (n), the drag resistivities near both oDP and sDP follow a typical n-alpha (alpha = 1.3-1.7) and T2 power law dependence as expected for the momentum transfer process and it also satisfies the layer reciprocity. In contrast, at low T, the layer reciprocity is broken in both oDP-oDP and sDP-oDP coupled regions that suggest dominant energy drag. Furthermore, quantitatively, the drag resistivities near sDPs are smaller than those near oDP and they deviate from T2 dependence below similar to 100 K. Our work demonstrates that the drag experiment can be used to investigate the coupling between the carriers in moire<acute accent> minibands and those in original Dirac bands which can be extended to other moire<acute accent> materials.