Abstract
The temperature dependence of the low-energy tail of the interband optical absorption band at the Peierls edge has been studied in halogen-bridged linear-chain complexes, [Pt(en(Formula presented)][Pt(en(Formula presented)(Formula presented)]((Formula presented)(Formula presented) and [Pt(en(Formula presented)][Pt(en(Formula presented)(Formula presented)]((Formula presented)(Formula presented), en being ethylenediamine. The absorption spectrum and its temperature dependence are explained well in terms of the subgap density of states of the one-dimensional electronic bands induced by the quantum vibration of Cl ions of the breathing mode. Both substances are found to have a dimensionless electron-phonon coupling constant of λ≊1.2, the zero-temperature gap parameter of (Formula presented)≊1.45 eV, and the transfer integral of (Formula presented)≊0.4 eV. Because of the strong electron-phonon coupling the temperature dependence of the energy gap is dominated by the self-energy effect; even at 0 K the self-energy amounts to 0.07-0.08 eV, being considerably greater than the self-energies in usual semiconductors. The role of the anharmonicity of the chainlike Pt-Cl bonds is discussed in relation to the origin of the large gap parameter.
| Original language | English |
|---|---|
| Pages (from-to) | 2390-2396 |
| Number of pages | 7 |
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 54 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1996 Jan 1 |
| Externally published | Yes |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics