Ballistic-hydrodynamic phase transition in flow of two-dimensional electrons

Abstract

Phase transitions are characterized by a sharp change in the type of dynamics of microparticles, and their description usually requires quantum mechanics. Recently, a peculiar type of conductors was discovered in which two-dimensional (2D) electrons form a viscous fluid. In this work we reveal that such electron fluid in high-quality samples can be formed from ballistic electrons via a phase transition. For this purpose, we theoretically study the evolution of a ballistic flow of 2D weakly interacting electrons with an increase of magnetic field and trace an emergence of a fluid fraction at a certain critical field. Such restructuring of the flow manifests itself in a kink in magnetic-field dependencies of the longitudinal and the Hall resistances. It is remarkable that the studied phase transition has a classical-mechanical origin and is determined by both the ballistic size effects and the electron-electron scattering. Our analysis shows that this effect was apparently observed in the recent transport experiments on 2D electrons in graphene and high-mobility GaAs quantum wells.

5 pages, 3 figures in the main text; 19 pages, 12 figures in the supplementary material

References in corpus (6)

• Geometric control of universal hydrodynamic flow in a two dimensional electron fluid
• Colossal negative magnetoresistance in a 2D electron gas
• Giant microwave photoresistivity in a high-mobility quantum Hall system
• Effects of Electron-Electron Scattering in Wide Ballistic Microcontacts
• The photoresponse of a two-dimensional electron gas at the second harmonic of the cyclotron resonance
• Giant Hall effect in the ballistic transport of two-dimensional electrons