Optical investigation of the metal—insulator transition regime in single-domain crystals of YBa2Cu3Ox
| Autor: | G. Bräuchle, A. Erb, Hilbert von Löhneysen, German Müller-Vogt, H. Claus, L. Widder, Hans Peter Geserich, N. Nücker, A. Zibold |
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| Rok vydání: | 1993 |
| Předmět: |
chemistry.chemical_classification
Superconductivity Materials science Condensed matter physics business.industry Energy Engineering and Power Technology Condensed Matter Physics Optical conductivity Spectral line Electron localization function Electronic Optical and Magnetic Materials Optics chemistry Electrical and Electronic Engineering Single domain Metal–insulator transition Anisotropy business Inorganic compound |
| Zdroj: | Physica C: Superconductivity. 212:365-371 |
| ISSN: | 0921-4534 |
| DOI: | 10.1016/0921-4534(93)90601-l |
| Popis: | We have determined the polarized reflectance spectra of YBa 2 Cu 3 O x crystals with single-domain (001) surfaces. The oxygen content of the crystals was varied between the superconducting limit x = 7 and the semiconducting limit x = 6. By fitting a Lorentz—Drude model as well as by performing a Kramers—Kronig transformation the spectral distribution of the in-plane tensor components of the cnergy loss function and of the conductivity function were obtained. Using the in-plane anisotropy of the optical properties we were able to separate the contribution of the CuO layers and of the CuO chains to the electronic transport properties. An analysis of the free-carrier concentration shows that there is no sharp metal—insulator transition if x is varied from x = 7 to x = 6. Rather, we find a broad transition regime extending from x = 6.5 to x = 6, where different consecutive localization processes of the free carriers are observed. |
| Databáze: | OpenAIRE |
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