Polarons with a twist

Abstract

We consider a polaron model where molecular \emph{rotations} are important. Here, the usual hopping between neighboring sites is affected directly by the electron-phonon interaction via a {\em twist-dependent} hopping amplitude. This model may be of relevance for electronic transport in complex molecules and polymers with torsional degrees of freedom, such as DNA, as well as in molecular electronics experiments where molecular twist motion is significant. We use a tight-binding representation and find that very different polaronic properties are already exhibited by a two-site model -- these are due to the nonlinearity of the restoring force of the twist excitations, and of the electron-phonon interaction in the model. In the adiabatic regime, where electrons move in a {\em low}-frequency field of twisting-phonons, the effective splitting of the energy levels increases with coupling strength. The bandwidth in a long chain shows a power-law suppression with coupling, unlike the typical exponential dependence due to linear phonons.

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References in corpus (2)

• Ab-initio study of model guanine assemblies: The role of pi-pi coupling and band transport
• Base pair dynamic assisted charge transport in DNA

Cited by in corpus (9)

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• Wave packet dynamics in chains with delayed electronic nonlinear response
• Tight-binding modeling of charge migration in DNA devices
• Tunneling system coupled to phonon: an analytical treatment
• Wave-packet rectification in nonlinear electronic systems: A tunable Aharonov-Bohm diode
• A density matrix approach to the dynamical properties of a two-site Holstein model
• Phonon Rabi-assisted tunneling in diatomic molecules