Recent Publications

Tchavdar Todorov

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  1. Title: Inelastic current-voltage spectroscopy of atomic wires

    Author(s): Montgomery M.J., Hoekstra J., Todorov T.N., Sutton A.P.

    Journal Of Physics-Condensed Matter, 15, No. 4, pp. 731-742 (FEB 5 2003)

    doi: 10.1088/0953-8984/15/4/312

    A tight-binding model is developed to describe the electron-phonon coupling in atomic wires under an applied voltage and to model, their inelastic current-voltage spectroscopy. Particular longitudinal phonons are found to have greatly enhanced coupling to the electronic states of the system. This leads to a large drop in differential conductance at threshold energies associated with these phonons. It is found that with increasing tension these energies decrease, while the size of the conductance drops increases, in agreement with experiment.

  2. Title: Electron-phonon interaction in atomic-scale conductors: Einstein oscillators versus full phonon modes

    Author(s): Montgomery M.J., Todorov T.N.

    Journal Of Physics-Condensed Matter, 15, No. 50, pp. 8781-8795 (DEC 24 2003)

    doi: 10.1088/0953-8984/15/50/011

    Two extreme pictures of electron-phonon interactions in nanoscale conductors are compared: one in which the vibrations are treated as independent Einstein atomic oscillators, and one in which electrons are allowed to couple to the full, extended phonon modes of the conductor. It is shown that, under a broad range of conditions, the full-mode picture and the Einstein picture produce essentially the same net power at any given atom in the nanojunction. The two pictures begin to differ significantly in the limit of low lattice temperature and low applied voltages, where electron-phonon scattering is controlled by the detailed phonon energy spectrum. As an illustration of the behaviour in this limit, we study the competition between trapped vibrational modes and extended modes in shaping the inelastic current-voltage characteristics of one-dimensional atomic wires.