Two-dimensional hydrodynamic viscous electron flow in annular Corbino rings

The concept of fluidic viscosity is ubiquitous in condensed-matter systems hosting a continuum where macroscopic properties can emerge. While an important property of liquids and some solids, only recently was the viscosity of an electron shown to play a role in electronic transport experiments. In this Letter, we present nonlocal electronic transport measurements in concentric annular rings formed in high-mobility two-dimensional electron gases, and the resulting data show that viscous hydrodynamic flow can occur far away from the source-drain current region. Our conclusion of viscous electronic transport is further corroborated by simulations of the Navier-Stokes equations that are found to be in agreement with our measurements below <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi>T</a:mi><a:mo>=</a:mo><a:mn>1</a:mn><a:mspace width="4pt"/><a:mtext>K</a:mtext></a:mrow></a:math>. Finally, this work emphasizes the key role played by viscosity via electron-electron <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mo>(</c:mo><c:mi>e</c:mi><c:mtext>−</c:mtext><c:mi>e</c:mi><c:mo>)</c:mo></c:mrow></c:math> interaction even when the electronic transport is restricted radially, and for which it should have played no major role.