Size and randomness effects on the temperature-dependent hopping conductivity of nanocrystalline chains

Abstract

Developing a renormalization group approach, we study the hopping conductivity of nanocrystalline chains with different site energies. Exact calculations show that many parameters including nanosizes, randomness of grain distributions, lattice distortions, site energies, transition rates, Fermi energy, and temperature influence the conductivity. Some new singular features, for example the frequency shift, the amplitude fluctuations, and the interchange between "peak" and "valley" behavior of the imaginary part of the conductivity can be caused by certain parameters mentioned above, while the interface distortions modulate mainly the overall amplitudes of the conductivity at the whole frequency region. PACS. 61.72.-y Defects and impurities in crystals; microstructure -64.60.Ak Renormalization-group, fractal, and percolation studies of phase transitions -71.24.+q Electronic structure of clusters and nanoparticles -72.15.-v Electronic conduction in metals and alloys

Broadband mean free path of diffuse light in polydisperse ensembles of scatterers for white light-emitting diode lighting

“…This situation is similar to the challenge in condensed matter physics to model charge transport in the presence of a very broad inhomogeneous distribution [35,36]. Therefore, we recommend that future studies of LED diffusers be done on materials that contain scatterers with well-defined sizes and shapes.…”