Pseudo-hydrodynamic flow of quasiparticles in semimetal WTe2 at room temperature

Abstract

Recently, much interest has emerged in fluid-like electric charge transport in various solid-state systems. The hydrodynamic behavior of the electronic fluid reveals itself as a decrease of the electrical resistance with increasing temperature (the Gurzhi effect) in narrow conducting channels, polynomial scaling of the resistance as a function of the channel width, substantial violation of the Wiedemann-Franz law supported by the emergence of the Poiseuille flow. Similarly to whirlpools in flowing water, the viscous electronic flow generates vortices, resulting in abnormal sign-changing electrical response driven by the backflow of electrical current. Experimentally, the presence of the hydrodynamic vortices was observed in low-temperature graphene as a negative voltage drop near the current-injecting contacts. However, the question of whether the long-ranged sign-changing electrical response can be produced by a mechanism other than hydrodynamics has not been addressed so far. Here we use polarization-sensitive laser microscopy to demonstrate the emergence of visually similar abnormal sign-alternating patterns in charge density in multilayer tungsten ditelluride at room temperature where this material does not exhibit true electronic hydrodynamics. We argue that this pseudo-hydrodynamic behavior appears due to a subtle interplay between the diffusive transport of electrons and holes. In particular, the sign-alternating charge accumulation in WTe2 is supported by the unexpected backflow of compressible neutral electron-hole current, which creates charge-neutral whirlpools in the bulk of this nearly compensated semimetal. We demonstrate that the exceptionally large spatial size of the charge domains is sustained by the long recombination time of electron-hole pairs.

14 pages, 3 figures + supplementary material

References in corpus (9)

• The Valley Hall Effect in MoS2 Transistors
• Hydrodynamics of electrons in graphene
• Hydrodynamics in graphene: Linear-response transport
• Experimental observation of anisotropic Adler-Bell-Jackiw anomaly in type-II Weyl semimetal WTe${}_{1.98}$ crystals at the quasi-classical regime
• Giant Gating Tunability of Optical Refractive Index in Transition Metal Dichalcogenide Monolayers
• Electron hydrodynamics dilemma: whirlpools or no whirlpools
• Magnetoresistance in two-component systems
• Direct evidence for charge compensation induced large magnetoresistance in thin WTe2
• Evidence for local spots of viscous electron flow in graphene at moderate mobility

Cited by in corpus (1)

• Interface engineering of van der Waals heterostructures towards energy-efficient quantum devices operating at high temperatures