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arXiv · 2511.11803

Evidence for atomic-scale vibron-mediated electron bunching

A. Maiti·M. Amato·V. S. Stolyarov·H. Aubin·J. Estève·F. Pistolesi·M. Aprili·F. Massee
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Abstract

Due to the Coulomb blockade effect, electrons rarely bunch during transport, a phenomenon observed only in a few specially engineered mesoscopic configurations. In this work, we introduce an atomically resolved shot-noise study to demonstrate the possibility of electron bunching through vibrational coupling which takes place in an atomically sized nano-electro-mechanical system. Using tunnelling spectroscopy, we observe signatures of vibron-assisted tunnelling on an Fe impurity in Bi$_2$Se$_3$. Notably, simultaneous shot-noise measurements at the centre of the vibrating impurity reveal super-Poissonian noise. In the absence of alternative sources of super-Poissonian noise, this implies vibronic-coupling-induced bunching of electrons during the tunnelling process through the impurity, as theoretically predicted decades ago. 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.

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A. Maiti, M. Amato, V. S. Stolyarov, H. Aubin, J. Estève, F. Pistolesi, M. Aprili, F. Massee. 2025-11-14. Evidence for atomic-scale vibron-mediated electron bunching. https://doi.org/10.1103/zvf5-wln4

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