Observation of the Dirac fluid and the breakdown of the Wiedemann-Franz law in graphene

Interactions between particles in quantum many-body systems can lead to collective behavior described by hydrodynamics. One such system is the electron-hole plasma in graphene near the charge-neutrality point, which can form a strongly coupled Dirac fluid. This charge-neutral plasma of quasi-relativistic fermions is expected to exhibit a substantial enhancement of the thermal conductivity, thanks to decoupling of charge and heat currents within hydrodynamics. Employing high-sensitivity Johnson noise thermometry, we report an order of magnitude increase in the thermal conductivity and the breakdown of the Wiedemann-Franz law in the thermally populated charge-neutral plasma in graphene. This result is a…

• NS
  National Science Foundation

  Award: DMR-1360789
• UD
  U.S. Department of Energy

  Award: DE-SC0012260
• JT
  John Templeton Foundation
• GA
  Gordon and Betty Moore Foundation

  Award: GBMF4543
• AF
  Agency for Science, Technology and Research
• NR
  National Research Foundation of Korea

  Award: 2012M3A7B4049966
• DA
  Defense Advanced Research Projects Agency
• MU
  Multidisciplinary University Research Initiative

  Award: W911NF-14-1-0003
• JS
  Japan Society for the Promotion of Science

  Award: 25106006
• AR
  Army Research Office

  Award: W911NF-14-1-0638