Anomalous current–electric field characteristics in transport through a nanoelectromechanical system
Phys. Rev. B 113, 085142 – Published 24 February, 2026
DOI: https://doi.org/10.1103/8zth-9bnj
Abstract
A thorough understanding of the correlation between electronic and mechanical degrees of freedom is crucial to the development of quantum devices in a nanoelectromechanical system (NEMS). In this work, we first establish a fully quantum mechanical approach for transport through a NEMS device, which is valid for arbitrary bias voltages, temperatures, and electromechanical couplings. We find anomalous current–electric field characteristics at a low bias from where the current decreases with a rising electric field. We reveal that this unique transport feature arises from a combined effect of mechanical motion and Coulomb blockade. At a large oscillation amplitude, the rapid increase of backward tunneling events, which is identified in both electron-counting statistics and the phase space of charge-resolved Wigner functions, suppresses the forward current due to prohibition of double occupation. In the opposite limit of strong damping, the oscillator dissipates its energy to the environment and relaxes to the ground state rapidly. Electrons then transport via the lowest vibrational state such that the net current and its corresponding noise have a vanishing dependence on the electric field.
