Non-coherent transport in carbon chains

作者：Gorjizadeh Narjes^*; Farajian Amir A; Kawazoe Yoshiyuki

来源：Journal of Physics: Condensed Matter , 2011, 23(7): 075301.

DOI：10.1088/0953-8984/23/7/075301

The effect of electron-phonon (e-ph) interaction on the conductance of carbon chains is investigated by a non-equilibrium Green's function technique combined with a four-orbitals-per-atom tight-binding Hamiltonian. The optimized structure of the chain is found to be the semiconducting polyyne type (center dot center dot center dot -C equivalent to C-C equivalent to C- center dot center dot center dot). Our results show that the conductance of a carbon chain attached to two fixed contacts decreases due to e-ph interaction, and this reduction is stronger for longitudinal phonon modes which decrease the hopping energy between carbon atoms. Study of individual phonon modes reveals that emission of longitudinal phonons is stronger than that of transverse modes at room temperature, while absorption of transverse phonons is dominant. Conductance at finite temperature is also studied by considering the overall phonon effects; this shows that the reduction of the conductance is stronger at higher temperatures. The results are explained on the basis of the unique features of the carbon chain band structure.

• 出版日期2011-2-23