8 research outputs found
Exact solution of electronic transport in semiconductors dominated by scattering on polaronic impurities
The scattering of electrons on impurities with internal degrees of freedom is
bound to produce the signatures of the scatterer's own dynamics and results in
nontrivial electronic transport properties. Previous studies of polaronic
impurities in low-dimensional structures, like molecular junctions and
one-dimensional nanowire models, have shown that perturbative treatments cannot
account for a complex energy dependence of the scattering cross section in such
systems. Here we derive the exact solution of polaronic impurities shaping the
electronic transport in bulk (3D) systems. In the model with a short-ranged
electron-phonon interaction, we solve for and sum over all elastic and
inelastic partial cross sections, abundant in resonant features. The
temperature dependence of the charge mobility shows the power-law dependence,
, with being highly sensitive to impurity
parameters. The latter may explain nonuniversal power-law exponents observed
experimentally, e.g. in high-quality organic molecular semiconductors.Comment: 5 pages, 6 figure
Dynamical Boson Stars
The idea of stable, localized bundles of energy has strong appeal as a model
for particles. In the 1950s John Wheeler envisioned such bundles as smooth
configurations of electromagnetic energy that he called {\em geons}, but none
were found. Instead, particle-like solutions were found in the late 1960s with
the addition of a scalar field, and these were given the name {\em boson
stars}. Since then, boson stars find use in a wide variety of models as sources
of dark matter, as black hole mimickers, in simple models of binary systems,
and as a tool in finding black holes in higher dimensions with only a single
killing vector. We discuss important varieties of boson stars, their dynamic
properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in
Relativity; major revision in 201