Laserlike Vibrational Instability in Rectifying Molecular Conductors

Jing Tao Lu, Per Hedegård, Mads Brandbyge

    Research output: Contribution to journalJournal articleResearchpeer-review

    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 nonequilibrium 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 the 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.
    Original languageEnglish
    JournalPhysical Review Letters
    Volume107
    Issue number4
    Pages (from-to)046801
    ISSN0031-9007
    DOIs
    Publication statusPublished - 2011

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