Curated by RSF Research Staff
Electrons Flowing like Liquid in Graphene start a New Wave of Physics
The mysterious electron, envisioned as billiard balls in Bohr’s model and as point particles in quantum field theory, remains to be truly understood. Studying the collective behavior and interaction properties of electrons could help us to further understand its intriguing nature.
The scattering properties and conductivity is a much-studied subject with the fundamental understanding that electron scattering decreases the conductivity. Crystal imperfections and high temperatures can both increase the scattering of electrons and thus effect the conductivity of the metal. High quality metals, with less impurities, allow the electron to travel further without being scattered and thus experience negligible resistance and increased conductivity. However, this negligible resistance – allowing for the ‘ballistic’ transport of electrons through a medium - is limited by the relationship between the distance the electron travels before scattering – its mean free path - and the dimension of the medium it is traveling through.
One such high quality metal is graphene, in which electrons can travel micron distances without scattering. Graphene therefore exhibits negligible resistance and high conductivity. However, in a recent study in the field of electron hydrodynamics, a team of researchers at the University of Manchester found that, for temperatures below 150 Kelvin, electron transport through graphene increases with increasing temperature. As well, the measured conductance, due to this contrary behavior, exceeds the maximum conductance possible for free electrons.
Professor Marco Polini and his team attribute this anomaly to “… collective movement of interacting electrons, which ‘shields’ individual carriers from momentum loss at sample boundaries.”
Further investigation into the collective movement of the electrons and their viscous effects on the conductivity will not only help determine the extent of the effects but as well it could improve our understanding on the nature of the electron.