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arXiv · 1103.1990

Laser-like vibrational instability in rectifying molecular conductors

Jing-Tao Lü·Per Hedegård·Mads Brandbyge
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Abstract

We study the damping of molecular vibrations due to electron-hole pair excitations in donor-acceptor(D-A) type molecular rectifiers. At finite voltage additional non-equilibrium electron-hole pair excitations involving both electrodes become possible, and contribute to the stimulated emission and absorption of phonons. We point out a generic mechanism for D-A molecules, where the stimulated emission can dominate beyond a certain voltage due to inverted position of the D and A quantum resonances. This leads to current-driven amplification (negative damping) of the phonons similar to laser-action. We investigate the effect in realistic molecular rectifier structures using first principles calculations.

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Jing-Tao Lü, Per Hedegård, Mads Brandbyge. 2011-03-10. Laser-like vibrational instability in rectifying molecular conductors. https://doi.org/10.1103/physrevlett.107.046801

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