First glimpse of hydrodynamic electron flow in 3D materials

Electrons flow through most materials more like a gas than a fluid, meaning they don't interact much with one another. It was long hypothesized that electrons could flow like a fluid, but only recent advances in materials and measurement techniques allowed these effects to be observed in 2D materials. In 2020, the labs of Amir Yacoby, Professor of Physics and of Applied Physics at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), Philip Kim, Professor of Physics and Professor Applied Physics at Harvard and Ronald Walsworth, formerly of the Department of Physics at Harvard, were among the first to image electrons flowing in graphene like water flows through a pipe.