Coulomb drag in graphene/hBN/graphene moiré heterostructures

Abstract

We report on the observation of Coulomb drag between graphene-hexagonal boron nitride (hBN) moiré heterostructure with a moiré wavelength of $\sim$14 nm and an intrinsic graphene with a lattice constant of $\sim$0.25 nm. By tuning carrier densities of each graphene layer independently, we find that the charge carriers in moiré mini-bands, i.e., near the satellite Dirac point (sDP), can be coupled with the massless Fermions near the original Dirac point (oDP), strongly enough to generate a finite drag resistivity. At high temperature ($T$) and large density ($n$), the drag resistivities near both oDP and sDP follow a typical $n^{-\alpha }$ ($\alpha =1.3\sim 1.7$) and $T^2$ 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 $T^2$ dependence below $\sim$100 K. These results suggest that the coupling between the carriers in moiré mini-bands and those in original Dirac bands may not be of a simple Fermi liquid nature.

11 pages, 7 figures

References in corpus (8)

• Emergence of Superlattice Dirac Points in Graphene on Hexagonal Boron Nitride
• Twist-controlled resonant tunnelling in graphene-boron nitride-graphene heterostructures
• Strong Coulomb drag and broken symmetry in double-layer graphene
• Coulomb Drag in Graphene
• Theory of Coulomb drag for massless Dirac fermions
• Topological Valley Currents in Bilayer Graphene/Hexagonal Boron Nitride Superlattices
• Ballistic transport spectroscopy of spin-orbit-coupled bands in monolayer graphene on WSe${}_2$
• Coulomb Drag between a Carbon Nanotube and Monolayer Graphene

Cited by in corpus (2)

• Dragging of electric current by hydrodynamic flow at charge neutrality
• Nonreciprocal Coulomb drag in electron bilayers