Exciton Optical Absorption in Self-Similar Aperiodic Lattices
Abstract
Exciton optical absorption in self-similar aperiodic one-dimensional systems is considered, focusing our attention on Thue-Morse and Fibonacci lattices as canonical examples. The absorption line shape is evaluated by solving the microscopic equations of motion of the Frenkel-exciton problem on the lattice, in which on-site energies take on two values, according to the Thue-Morse or Fibonacci sequences. Results are compared to those obtained in random lattices with the same stechiometry and size. We find that aperiodic order causes the occurrence of well-defined characteristic features in the absorption spectra which clearly differ from the case of random systems, indicating a most peculiar exciton dynamics. We successfully explain the obtained spectra in terms of the two-center problem. This allows us to establish the origin of all the absorption lines by considering the self-similar aperiodic lattices as composed of two-center blocks, within the same spirit of the renormalization group ideas.
Keywords
Cite
@article{arxiv.cond-mat/9407018,
title = {Exciton Optical Absorption in Self-Similar Aperiodic Lattices},
author = {E. Macia and F. Dominguez-Adame},
journal= {arXiv preprint arXiv:cond-mat/9407018},
year = {2009}
}
Comments
16 pages in REVTeX 3.0. 2 figures on request to F. D-A ([email protected])