We derive a general result that can be used to evaluate and compare the transconductance of different field-effect mechanisms in molecular transistors, both electrostatic and conformational. The electrostatic component leads to the well-known thermal limit in the absence of tunneling. We show that in a standard three-terminal geometry and in the absence of strong electron-phonon coupling, the conformational component can lead to significant advantages only if the molecular dipole moment \mu is comparable to et_ox, t_ox being the thickness of the oxide. Surprisingly this conclusion is independent of the ``softness'' of the conformational modes involved, or other geometrical factors. Detailed numerical results for specific examples are presented in support of the analytical results.
@article{arxiv.cond-mat/0212166,
title = {Gating of a molecular transistor: Electrostatic and Conformational},
author = {Avik W. Ghosh and Titash Rakshit and Supriyo Datta},
journal= {arXiv preprint arXiv:cond-mat/0212166},
year = {2016}
}
Comments
Small corrections and typos, rephrased descriptions and added footnotes. Accepted, Nano Letters (tentatively scheduled for April 2004)