Photoexcitations in the strongly correlated 1D electron system of halogen-bridged Ni compounds

Citation
H. Okamoto et al., Photoexcitations in the strongly correlated 1D electron system of halogen-bridged Ni compounds, J LUMINESC, 87-9, 2000, pp. 204-206
Citations number
8
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF LUMINESCENCE
ISSN journal
0022-2313 → ACNP
Volume
87-9
Year of publication
2000
Pages
204 - 206
Database
ISI
SICI code
0022-2313(200005)87-9:<204:PITSC1>2.0.ZU;2-G
Abstract
To study nature of photo-excited states in one-dimensional (1D) strongly co rrelated electron systems, we have synthesized the halogen(X)-bridged Ni co mpounds, [Ni(chxn)(2)X]Y-2 (X = Cl or Br; Y = Cl, Br, NO3 or ClO4; (chxn) = cyclohexanediamine), which have 1D Ni-X chains. These Ni compounds are cha rge-transfer (CT) insulators, showing strong C-T transitions from the occup ied halogen p band to the Ni d upper Hubbard band. The CT transition energi es can be systematically controlled from 1.3 to 2.0 eV by the choice of the bridging-halogen ions X and the counter ions Y. From the excitation profil es of the photoconductivities. excitonic effects in the Ni-X chains have be en found to depend strongly on the degree of pd hybridization. (C) 2000 Els evier Science B.V. All rights reserved.