Superballistic paradox in electron fluids: Evidence of tomographic transport

Abstract

Electron hydrodynamics encompasses the exotic fluid-like behavior of electrons in two-dimensional materials such as graphene. It accounts for superballistic conduction, also known as the Gurzhi effect, where increasing temperature reduces the electrical resistance. In analogy with conventional fluids, the Gurzhi effect is only expected in the hydrodynamic regime, with the decrease in the resistance occurring at intermediate temperatures. Nonetheless, experiments on electron fluids consistently show that superballistic conduction starts at close-to-zero temperatures. To address this paradox, we study hydrodynamic flow, and we find that replacing the classical dynamics with tomographic dynamics, where only head-on collisions are allowed between electrons, solves the dilemma. The latter strengthens superballistic conduction, with potential applications in low-dissipation devices, and explains its differences with the Molenkamp effect and conventional fluids dynamics. Our study reveals that the superballistic paradox is resolved by considering the electrons not as classical particles but as fermions.

References in corpus (6)

• Hydrodynamic approach to two-dimensional electron systems
• Temperature dependence of the conductivity of ballistic graphene
• Observation of current whirlpools in graphene at room temperature
• Collective modes in interacting two-dimensional tomographic Fermi liquids
• Effects of Electron-Electron Scattering in Wide Ballistic Microcontacts
• Diffusion of photo-excited holes in viscous electron fluid

Cited by in corpus (2)

• Slip electron flow in GaAs microscale constrictions
• Tomographic collective modes in a magnetic field