Hot electrons reveal electronic collisions may raise resistance in twisted graphene

A study of twisted graphene indicates that collisions between electrons may contribute to rising electrical resistance when the material’s electrons are heated. The result focuses on a longstanding question in condensed-matter physics: what is responsible when a conductor becomes more resistant to electrical current at higher temperatures?

Electrical resistance can increase because current-carrying electrons are scattered by phonons, the vibrations of a material’s atomic lattice. But electrons can also collide with one another. Conventional temperature measurements make it difficult to separate those effects because heating a material typically raises the temperature of both its electrons and its lattice at the same time.

The work uses hot electrons to help distinguish the electronic contribution from lattice-related scattering. In twisted graphene—formed by stacking graphene layers at a relative angle—the findings suggest electron-electron collisions may themselves raise resistance, rather than acting only as an indirect part of the material’s response to heating.

Separating these mechanisms could help researchers better understand how electrical transport works in graphene-based materials and other systems where interactions among electrons are important.