Due to the Coulomb blockade effect, electrons typically tunnel into a localized state one by one, showing antibunching behavior. However, theory predicts that strong vibronic coupling can generate electron bunching locally, yet direct atomic-scale evidence has remained elusive. In this Letter, we report an atomically resolved shot-noise study probing the transport statistics of single-electron tunneling in an atomic impurity coupled to a vibrational mode. Conventional time-averaged conductance spectroscopy reveals clear signatures of vibron-assisted tunneling in this atomically sized nanoelectromechanical system. Simultaneous shot-noise measurements at the impurity center show super-Poissonian noise, providing direct evidence that vibronic coupling drives electron bunching during tunneling. As a future outlook, if coherence between electrons can be implemented, vibron-mediated electron bunching at single atomic sites may be exploited as a local injection source of 𝑁-paired electrons.
See the FOCUS made by Physical Review Letters here: https://physics.aps.org/articles/v19/s75
Vibrations Make Electrons Team Up
Reference
Evidence for Atomic-Scale Vibron-Mediated Electron Bunching
A. Maiti, M. Amato, V. S. Stolyarov, H. Aubin, J. Estève, F. Pistolesi, M. Aprili, and F. Massee
Phys. Rev. Lett. 136, 236501 (2026) Editor’s suggestion and Featured in Physics
doi:https://journals.aps.org/prl/abstract/10.1103/zvf5-wln4
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Freek Massee