Congratulations, Ben List and David MacMillan!

Lead telluride is an important thermoelectric material but its metal-to-semiconductor transition above 230 °C is not fully understood. Here, atomic-resolution transmission electron microscopy provides structural insights into this transition, explaining the metallic behavior by local structural changes leading to the formation of a dislocation network within the rock salt structure.

Recent research suggested that hydrodynamic electron flow in 3D conductors was possible, but exactly how it happened or how to observe it remained unknown. Until now. 
A team of researchers from Harvard, MIT and the Max Planck Institute Chemical Physics of Solids developed a theory to explain how hydrodynamic electron flow could occur in 3D materials and observed it for the first time using a new imaging technique.