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Diffusion of Frenkel excitons in anisotropic crystals
Author(s) -
Glushko E. Ya.,
Efremov N. A.
Publication year - 1983
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221150224
Subject(s) - anisotropy , exciton , isotropy , tensor (intrinsic definition) , condensed matter physics , physics , diffusion , effective mass (spring–mass system) , quantum mechanics , geometry , mathematics
The temperature dependence of the diffusion tensor D ik (T) of coherent excitons in anisotropic molecular crystals is considered. The influence of such exciton energetic band peculiarities as effective mass tensor anisotropy and nonanalyticity of exciton energy on the dependence D ik (T) is analyzed. It is shown that the dependence D ∼ T −1/2 , which is characteristic of isotropic crystals, is retained only at weak anisotropy of the effective mass tensor m max /m min ≈ 1 with no regard for nonanalyticity. At the same time, at great values of the nonanalytic part of the exciton energy the diffusion tensor component dependences vary from D aa ≈ D cc ∼ T −1 ≪ D bb ∼ T −2 at weak anisotropy of the effective mass tensor to D aa ≈ D cc ≈ const ≪ D bb ∼ T −3/4 at strong anisotropy.