Anomalous Coulomb Drag between InAs Nanowire and Graphene Heterostructures

Correlated charge inhomogeneity breaks the electron-hole symmetry in two-dimensional bilayer heterostructures, responsible for non-zero drag appearing at the charge neutrality point. Although several theories predict this phenomenon, there is no consensus over the actual mechanism responsible for it. Here we report, Coulomb drag in a novel drag system consisting of a two-dimensional (2D) graphene and a one dimensional (1D) InAs nanowire (NW) heterostructures. For monolayer graphene (MLG)-NW heterostructures we observe an unconventional drag resistance peak near the Dirac point due to the correlated inter-layer charge puddles, which decreases monotonically with temperature (∼T^-2) but increases rapidly with the magnetic field (∼B²). These anomalous responses together with the mismatched thermal conductivities of graphene and NWs establish the energy drag as the responsible mechanism of Coulomb drag in MLG-NW devices. In contrast, for bilayer graphene (BLG)-NW devices the drag voltage reverses sign across the Dirac Point, consistent with momentum drag but remains almost constant with magnetic field and temperature. These Coulomb drag measurements in 2D-1D systems, hitherto not reported before, will pave the future realization of correlated condensate states in novel systems.