Superballistic conduction in hydrodynamic antidot graphene superlattices

TL;DR

This paper demonstrates superballistic electron conduction in graphene antidot superlattices, revealing geometry-induced hydrodynamic effects and non-monotonic magnetic field dependence, with implications for designing devices with collective electron flow.

Contribution

It introduces graphene antidot superlattices as a new platform to observe and analyze hydrodynamic electron flow and superballistic conduction, highlighting the role of geometry and magnetic field effects.

Findings

Enhanced superballistic conduction observed in antidot lattices.

Non-monotonic behavior of conduction with magnetic field.

Scaling laws for transport regimes in antidot superlattices.

Abstract

Viscous electron flow exhibits exotic signatures such as superballistic conduction. In order to observe hydrodynamics effects, a 2D device where the current flow is as inhomogeneous as possible is desirable. To this end, we build three antidot graphene superlattices with different hole diameters. We measure their electrical properties at various temperatures and under the effect of a perpendicular magnetic field. We find an enhanced superballistic effect, suggesting the effectiveness of the geometry at bending the electron flow. In addition, superballistic conduction, which is related to a transition from a non-collective to a collective regime of transport, behaves non-monotonically with the magnetic field. We also analyze the device resistance as a function of the size of the antidot superlattice to find characteristic scaling laws describing the different transport regimes. We prove that the antidot superlattice is a convenient geometry for realizing hydrodynamic flow and provide valuable explanations for the technologically relevant effects of superballistic conduction and scaling laws.