Charge transfer through single molecule contacts: How reliable are rate descriptions?

• Denis Kast,
• L. Kecke and
• J. Ankerhold

Beilstein J. Nanotechnol. 2011, 2, 416–426, doi:10.3762/bjnano.2.47

• interested in the low temperature domain θ > 1 where thermal broadening of phonon levels is small such that discrete steps appear in the I–V characteristics. Qualitatively, seen from the dynamics of the phonon mode, two regimes can be distinguished according to the adiabaticity parameter ∑/ω0 = σ: For σ < 1

• backward (with prime) rates are the basic ingredients for the approximate treatment, see text for details. I–V-characteristics for symmetric coupling ∑L = ∑R and for varying electron–phonon coupling m0 at inverse temperature θ = 25 (solid) and θ = 10 (dashed). Mean phonon number in nonequilibrium for eV

• = 3ω0 and versus the electron–phonon coupling m0. Phonon number distribution in nonequilibrium for eV = 5ω0, m0 = 0.5 and kBT/ω0 = 0.1 (histogram). The solid line depicts a fit to a Boltzmann distribution. See text for details. I–V-characteristics for equilibrated (solid) and nonequilibrated (dotted