Electrically biased metal nanostructures are at the core of innovative multifunctional integrated devices that control the flow of electrons and photons at the nanoscale. They are based on plasmonic structures that create strongly confined fields, typically associated with large temperature gradients. These thermal effects may generate artifact responses detrimental to the desired operation. We show here how a biasing polarity and a local optical excitation asymmetry of a generic geometry – a nanoscale constriction – interplay thermally to modify the diffusive electron transport in out-of-equilibrium conditions. Our experimental results are accompanied with computational electromagnetism and multiphysics simulations.
