32 research outputs found
Local distribution approach to disordered binary alloys
We study the electronic structure of the binary alloy and (quantum)
percolation model. Our study is based on a self-consistent scheme for the
distribution of local Green functions. We obtain detailed results for the
density of states, from which the phase diagram of the binary alloy model is
constructed, and discuss the existence of a quantum percolation threshold.Comment: 9 pages, 8 figures. A few minor changes, 1 figure adde
Solution of the Holstein polaron anisotropy problem
We study Holstein polarons in three-dimensional anisotropic materials. Using
a variational exact diagonalization technique we provide highly accurate
results for the polaron mass and polaron radius. With these data we discuss the
differences between polaron formation in dimension one and three, and at small
and large phonon frequency. Varying the anisotropy we demonstrate how a polaron
evolves from a one-dimensional to a three-dimensional quasiparticle. We thereby
resolve the issue of polaron stability in quasi-one-dimensional substances and
clarify to what extent such polarons can be described as one-dimensional
objects. We finally show that even the local Holstein interaction leads to an
enhancement of anisotropy in charge carrier motion.Comment: 6 pages, 7 figures; extended version accepted for publication in
Phys. Rev.