Observation of giant and tuneable thermal diffusivity of Dirac fluid at room temperature
arXiv:2008.04189 · doi:10.1038/s41565-021-00957-6
Abstract
Conducting materials typically exhibit either diffusive or ballistic charge transport. However, when electron-electron interactions dominate, a hydrodynamic regime with viscous charge flow emerges (1-13). More stringent conditions eventually yield a quantum-critical Dirac-fluid regime, where electronic heat can flow more efficiently than charge (14-22). Here we observe heat transport in graphene in the diffusive and hydrodynamic regimes, and report a controllable transition to the Dirac-fluid regime at room temperature, using carrier temperature and carrier density as control knobs. We introduce the technique of spatiotemporal thermoelectric microscopy with femtosecond temporal and nanometre spatial resolution, which allows for tracking electronic heat spreading. In the diffusive regime, we find a thermal diffusivity of 2,000 cm/s, consistent with charge transport. Remarkably, during the hydrodynamic time window before momentum relaxation, we observe heat spreading corresponding to a giant diffusivity up to 70,000 cm/Vs, indicative of a Dirac fluid. These results are promising for applications such as nanoscale thermal management.
References in corpus (29)
- Hot Carrier-Assisted Intrinsic Photoresponse in Graphene
- Negative local resistance caused by viscous electron backflow in graphene
- Observation of the Dirac fluid and the breakdown of the Wiedemann-Franz law in graphene
- Ultrafast collinear scattering and carrier multiplication in graphene
- Evidence for hydrodynamic electron flow in PdCoO
- Ultrafast Photoluminescence from Graphene
- Superballistic flow of viscous electron fluid through graphene constrictions
- Hydrodynamics of electrons in graphene
- Electron Viscosity, Current Vortices and Negative Nonlocal Resistance in Graphene
- Imaging viscous flow of the Dirac fluid in graphene
- Measuring Hall Viscosity of Graphene's Electron Fluid
- Visualizing Poiseuille flow of hydrodynamic electrons
- Electrical and Thermal Transport at the Planckian Bound of Dissipation in the Hydrodynamic Electron Fluid of WP2
- Quantum critical scaling in graphene
- The electronic thermal conductivity of graphene
- Slow imbalance relaxation and thermoelectric transport in graphene
- Enhanced Thermoelectric Power in Graphene: Violation of the Mott Relation By Inelastic Scattering
- Out-of-plane heat transfer in van der Waals stacks: electron-hyperbolic phonon coupling
- Transport in inhomogeneous quantum critical fluids and in the Dirac fluid in graphene
- Phonon hydrodynamics and ultrahigh-room-temperature thermal conductivity in thin graphite
- Tracking ultrafast hot-electron diffusion in space and time by ultrafast thermo-modulation microscopy
- Hydrodynamics in graphene: Linear-response transport
- Viscous electron fluids
- Scanning Gate Microscopy in a Viscous Electron Fluid
- Hot carrier diffusion in graphene
- Interacting Electrons in Graphene: Fermi Velocity Renormalization and Optical Response
- Transport coefficients of graphene: Interplay of impurity scattering, Coulomb interaction, and optical phonons
- Breakdown of the Wiedemann-Franz law in AB-stacked bilayer graphene
- Graphene - a nearly perfect fluid
Cited by in corpus (15)
- Hydrodynamic approach to two-dimensional electron systems
- Giant magnetoresistance of Dirac plasma in high-mobility graphene
- Light-Driven Nanoscale Vectorial Currents
- Evidence for local spots of viscous electron flow in graphene at moderate mobility
- Anomalous terahertz photoconductivity caused by the superballistic flow of hydrodynamic electrons in graphene
- Universality in quantum critical flow of charge and heat in ultra-clean graphene
- Extreme electron-hole drag and negative mobility in the Dirac plasma of graphene
- Transition from acoustic plasmon to electronic sound in graphene
- A pre-time-zero spatiotemporal microscopy technique for the ultrasensitive determination of the thermal diffusivity of thin films
- Strong-Field Bloch Electron Interferometry for Band Structure Retrieval
- Interlayer electron-hole friction in tunable twisted bilayer graphene semimetal
- Hydrodynamics of the electronic Fermi liquid: a pedagogical overview
- Performance limits due to thermal transport in graphene single-photon bolometers
- On the Wiedemann-Franz law violation in Graphene and quark-gluon plasma systems
- Electron viscosity and device-dependent variability in four-probe electrical transport in ultra-clean graphene field-effect transistors