Exciton Optical Absorption in Self-Similar Aperiodic Lattices

E. Macia; F. Dominguez-Adame

doi:10.1103/physrevb.50.16856

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Exciton Optical Absorption in Self-Similar Aperiodic Lattices

E. Macia·F. Dominguez-Adame

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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.

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E. Macia, F. Dominguez-Adame. 1994-07-04. Exciton Optical Absorption in Self-Similar Aperiodic Lattices. https://doi.org/10.1103/physrevb.50.16856

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