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Current-induced nonequilibrium vibrations in single-molecule devices

Jens Koch·Matthias Semmelhack·Felix von Oppen·Abraham Nitzan
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Abstract

Finite-bias electron transport through single molecules generally induces nonequilibrium molecular vibrations (phonons). By a mapping to a Fokker-Planck equation, we obtain analytical scaling forms for the nonequilibrium phonon distribution in the limit of weak electron-phonon coupling $λ$ within a minimal model. Remarkably, the width of the phonon distribution diverges as $\simλ^{-α}$ when the coupling decreases, with voltage-dependent, non-integer exponents $α$. This implies a breakdown of perturbation theory in the electron-phonon coupling for fully developed nonequilibrium. We also discuss possible experimental implications of this result such as current-induced dissociation of molecules.

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Jens Koch, Matthias Semmelhack, Felix von Oppen, Abraham Nitzan. 2006-04-16. Current-induced nonequilibrium vibrations in single-molecule devices. https://doi.org/10.1103/physrevb.73.155306

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