Cryogenic shock exfoliation plus low-pressure assembly produces large-area, ultrahigh-mobility rhombohedral graphene devices with uniform spin magnetism and hydrodynamic electron flow.
Imaging flat band electron hydrodynamics in biased bilayer graphene
2 Pith papers cite this work. Polarity classification is still indexing.
abstract
Hydrodynamic electron transport arises when carrier kinetics are dominated by interelectron collisions rather than the relaxation of momentum out of the electron system. In recent years, signatures of electron hydrodynamics have been reported in graphene devices owing to the low disorder and weak electron-phonon coupling. However, these experiments have been performed in regimes where the carrier mass is light, and the electron-electron collision length--though smaller than corresponding lengths for phonon or impurity scattering--remains large in absolute terms, typically several hundred nanometers. This restricts hydrodynamic transport phenomena to large length scales, limiting miniaturization of devices based on hydrodynamic flow. The advent of dual-gated rhombohedral graphene multilayers introduces a new route toward enhanced hydrodynamic behavior via their large--and tunable--effective mass. Here, we employ a scanning superconducting magnetic sensor to image local current flow in dual-gated bilayer graphene. Exploiting a sample geometry sensitive to both laminar and vortical flow, we identify three distinct transport regimes--ballistic, hydrodynamic, and diffusive--across the full phase space spanned by carrier density and displacement field. The strongest hydrodynamic transport is observed in the flat band regime, where fitting our results to a unified Boltzmann transport model reveals the electron-electron scattering length to be comparable to the Fermi wavelength of ~50 nm. High-current measurements, meanwhile, reveal striking nonlinearities in the flow pattern. Our results pave the way for miniaturized electronic devices based on linear and nonlinear electron hydrodynamics.
fields
cond-mat.mes-hall 2years
2026 2representative citing papers
A linearized Boltzmann model in five-terminal geometry shows current partition diagnoses ballistic-hydrodynamic-Ohmic crossover and extracts momentum-relaxing and conserving scattering rates.
citing papers explorer
-
Cryogenic shock exfoliation for ultrahigh mobility rhombohedral graphite nanoelectronics
Cryogenic shock exfoliation plus low-pressure assembly produces large-area, ultrahigh-mobility rhombohedral graphene devices with uniform spin magnetism and hydrodynamic electron flow.
-
Characterizing electronic scattering rates with transport in multiterminal devices
A linearized Boltzmann model in five-terminal geometry shows current partition diagnoses ballistic-hydrodynamic-Ohmic crossover and extracts momentum-relaxing and conserving scattering rates.