Low-temperature electronic transport through macromolecules and characteristics of intramolecular electron transfer

The effect of dephasing on the thermoelectric efficiency of molecular junctions

In this work we report the results of theoretical analysis of the effect of the thermal environment on the thermoelectric efficiency of molecular junctions. The environment is represented by two thermal phonon baths associated with the electrodes, which are kept at different temperatures. The analysis is carried out using the Buttiker model within the scattering matrix formalism to compute electron transmission through the system. This approach is further developed so that the dephasing parameters are expressed in terms of relevant energies, including the thermal energy, strengths of coupling between the molecular bridge and the electrodes and characteristic energies of electron-phonon interactions. It is shown that the latter significantly affect thermoelectric efficiency by destroying the coherency of electron transport through the considered system.

On the dissipative effects in the electron transport through conducting polymer nanofibers

Here, the author studies the effects of stochastic nuclear motions on the electron transport in doped polymer fibers assuming the conducting state of the material. The author treats conducting polymers as granular metals and applies the quantum theory of conduction in mesoscopic systems to describe the electron transport between metalliclike granules. To analyze the effects of nuclear motions, the author mimics them by a phonon bath and includes electron-phonon interactions in consideration. The results show that the phonon bath plays a crucial part in the intergrain electron transport at moderately low and room temperatures, suppressing the original intermediate state for the resonance electron tunneling and producing new states which support the electron transport. Also, the temperature dependence of the magnitudes of the peaks in the electron transmission corresponding to these new states is analyzed.