Coulomb Drag between a Carbon Nanotube and Monolayer Graphene

Abstract

We have measured Coulomb drag between an individual single-walled carbon nanotube (SWNT) as a one-dimensional (1D) conductor and the two-dimensional (2D) conductor monolayer graphene, separated by a few-atom-thick boron nitride layer. The graphene carrier density is tuned across the charge neutrality point (CNP) by a gate, while the SWNT remains degenerate. At high temperatures, the drag resistance changes sign across the CNP, as expected for momentum transfer from drive to drag layer, and exhibits layer exchange Onsager reciprocity. We find that layer reciprocity is broken near the graphene CNP at low temperatures due to nonlinear drag response associated with temperature dependent drag and thermoelectric effects. The drag resistance shows power-law dependences on temperature and carrier density characteristic of 1D-2D Fermi liquid/Dirac fluid drag. The 2D drag signal at high temperatures decays with distance from the 1D source slower than expected for a diffusive current distribution, suggesting additional interaction effects in the graphene in the hydrodynamic transport regime.

Coulomb drag between quantum wires in the quasi-1D regime.

“…However, subsequent theoretical advances [29][30][31][32][33] have highlighted that, in mesoscopic structures, alternate drag-inducing mechanisms involving rectification of charge fluctuations could explicitly break Onsager's relations. Recent observations consistent with these novel theories have been reported in quantum dots [34], in nanowires coupled to graphene [35] as well as in superconducting [36,37] and topological wires [38]. Understanding the material and parametric considerations behind the onset of this alternate draginducing mechanism is crucial for future developments in the field of coupled 1D systems.…”

“…However it is likely that a combination of the large subband occupancy in the wires, the significant interwire separation and the sample innate disorder could be the source of these fundamental differences in the nature of the dominant drag-inducing mechanism. It should also be noted that, as highlighted by recent studies [35,36,38,52], observations of a negative and/or nonreciprocal CD is not uncommon in mesoscopic systems. Additional experimental and theoretical work will be required to determine the universality of rectificationinduced drag across various material platforms and to assess the parametric onset of both momentum transfer and rectification induced drag.…”

Manipulating electron waves in graphene using carbon nanotube gating

“…Recent advancement in the fabrication of nanostructures, and, in particular, efficient transfer and manipulation of CNTs for the assembly of nanodevices [36][37][38][39][40], opens up possibilities for precise control over the CNT position and orientation. Using CNT as a gate for graphene has been proposed in theoretical works [41][42][43] as well as realized experimentally in the capacitive measurement of graphene's local density of states [44] and Coulomb drag between graphene and CNT [45]. However, no transport investigations of guiding by a CNT-induced channel have been conducted so far.…”