Interplay of disorder and electron-phonon coupling in models of polyacetylene

Journal Article · Fri May 15 04:00:00 EDT 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.35.7533· OSTI ID:6092867

Phillpot, S R; Baeriswyl, D; Bishop, A R; Lomdahl, P S

We present, within the Su-Schrieffer-Heeger model, analytical and numerical calculations of the effects of two types of model impurities, namely bond and site, on the statics and dynamics of the lattice structure, and adiabatically associated one-electron spectrum, of trans-polyacetylene. For both types of impurities two or more localized electronic levels are produced, which may be in the intragap region or beyond the ..pi..-band edges (ultraband). Linear-response calculations of the induced lattice defects are in good agreement with the numerical calculations. A numerical study of kink-impurity dynamics shows that a kink may be reflected, transmitted, or trapped by the impurity depending on both the impurity strength and the topology of the impurity-induced lattice defect. A kink trapped by a site impurity of sufficient strength is found to have no midgap level but is supported by a level beyond the edge of the ..pi.. band. We also find that the trapping of a kink by a site impurity may result in the production of a potentially long-lived polaron. Such strong electron-phonon renormalization effects on the electronic structure in the presence of disorder are also found for bond impurities, where ultraband levels may form at the expense of more localized intragap levels. Photoexcitation experiments in the defected system produce the full range of nonlinear excitations: kinks, breathers, polarons, excitons, and trapped kinks. We calculate the optical absorption spectra in typical experiments and identify extrinsic intragap absorption.

• Research Organization: Xerox Webster Research Center, Webster, New York 14580 and Center for Nonlinear Studies and Theoretical Division, Los Alamos National Laboratory, The University of California, Los Alamos, New Mexico 87545
• OSTI ID: 6092867
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 35:14; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure & Phase Studies
360603* -- Materials-- Properties
ABSORPTION SPECTRA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON-PHONON COUPLING
HAMILTONIANS
HYDROCARBONS
IMPURITIES
LATTICE PARAMETERS
MATHEMATICAL MODELS
MATHEMATICAL OPERATORS
MOLECULAR MODELS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
POLYACETYLENES
POLYENES
QUANTUM OPERATORS
SPECTRA
SUPERCONDUCTIVITY