Researchers explore a hydrodynamic semiconductor where electrons flow like water

https://phys.org/news/2022-07-explore-hydrodynamic-semiconductor-electrons.html

"negatively charged electrons and positively charged "holes" simultaneously carry current. They found that this current can be described with just two "hydrodynamic" equations: one describing how the electrons and holes slide against each other, and a second for how all of the charges move together through the atomic lattice of the material... tuned in a way that allows conductivity to be turned on and off, and the hydrodynamic behavior was prominent even at room temperature"