Solitons, polarons, and phonons in the infinite polyyne chain

Journal Article · Mon Sep 15 00:00:00 EDT 1986 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.34.4139· OSTI ID:5062328

Rice, M J; Phillpot, S R; Bishop, A R; Campbell, D K

The infinite polyyne chain, ( CXC )/sub infinity/, or polyyne, is interpreted as a Peierls distorted one-dimensional metal with strong intrinsic electron-phonon coupling at the half-filled band level. Because there are two degenerate ..pi..-electron bands in polyyne the effective internal degeneracy (N-italic) of the electrons is 4, rather than 2 as in the model of polyacetylene. This leads to a rich variety of kink-soliton and polaron states and, in the limit of a continuum description, to the interesting result that polyyne is an approximate physical realization of an N-italic = 4 Gross-Neveu model relativistic field theory. The low-lying electronic excitations of the polymer are kink-solitons with charges 0, +- e-italic, and +- 2e-italic. The lowest-lying ionization states are a polaron, a bipolaron, and a tripolaron, with charges +- e-italic, +- 2e-italic, and +- 3e-italic, respectively. Photoexcitation of the polymer leads to a n-italice-italicu-italict-italicr-italica-italicl-italic polaron consisting of an electron and a hole bound by lattice distortion (''polarexciton''). Both the soliton and the polarons involve the appearance of localized intragap levels that are n-italico-italict-italic present in the ground state. Moreover, a localized e-italicx-italicc-italici-italict-italice-italicd-italic state exists for the polaron, while photoexcitation of the bipolaron and the tripolaron result in soliton-antisoliton pair production. Photoinduced absorption measurements on long f-italici-italicn-italici-italict-italice-italic polyynes in solution should be able to confirm the photogeneration of the polarexciton.

• Research Organization: Xerox Corporation, Webster Research Center (0114-38D), 800 Phillips Road, Webster, New York 14580
• OSTI ID: 5062328
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 34:6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
POLYENES
PHONONS
POLARONS
SOLITONS
BAND THEORY
CARBON COMPOUNDS
DOPED MATERIALS
ELECTRON-PHONON COUPLING
ELECTRONIC STRUCTURE
FIELD THEORIES
IONIZATION
HYDROCARBONS
MATERIALS
ORGANIC COMPOUNDS
QUASI PARTICLES
360404* - Materials- Polymers & Plastics- Physical Properties- (-1987)