Journal article ยท Preprint article
Nonequilibrium electron-vibration coupling and conductance fluctuations in a C-60 junction
We investigate chemical bond formation and conductance in a molecular C-60 junction under finite bias voltage using first-principles calculations based on density functional theory and nonequilibrium Green's functions (DFT-NEGF). At the point of contact formation we identify a remarkably strong coupling between the C-60 motion and the molecular electronic structure.
This is only seen for positive sample bias, although the conductance itself is not strongly polarity dependent. The nonequilibrium effect is traced back to a sudden shift in the position of the voltage drop with a small C-60 displacement. Combined with a vibrational heating mechanism we construct a model from our results that explain the polarity-dependent two-level conductance fluctuations observed in recent scanning tunneling microscopy (STM) experiments [N.
Neel et al., Nano Lett. 11, 3593 (2011)]. These findings highlight the significance of nonequilibrium effects in chemical bond formation/breaking and in electron-vibration coupling in molecular electronics.
Language: | English |
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Year: | 2012 |
Pages: | 9 |
ISSN: | 1550235x , 10980121 and 01631829 |
Types: | Journal article and Preprint article |
DOI: | 10.1103/PhysRevB.86.245417 |
ORCIDs: | Brandbyge, Mads |