Conductivity in Cuprates Arises from Two Different Sources: One-Electron Exchange and Disproportionation
| العنوان: | Conductivity in Cuprates Arises from Two Different Sources: One-Electron Exchange and Disproportionation |
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| المؤلفون: | Larsson, Sven, 1941 |
| المصدر: | Journal of Superconductivity and Novel Magnetism. 30(2):275-285 |
| مصطلحات موضوعية: | Resistivity, Superconductivity (SC), Doping level, Metal-metal charge transfer (CT), Pseudogap, Mobility, Hubbard-U, Cuprates, Vibronic states |
| الوصف: | Simulation of the resistivity in the normal state of doped La2-x Sr (x) CuO4 has been performed using a hopping model based on Marcus theory. The results are in substantial agreement with experimental results. At oxidative doping, Cu(III) sites are formed and electron mobility possible due to hopping: Cu(III)Cu(II) -> Cu(II)Cu(III) (one-electron exchange). In the underdoped, non-metallic region, the resistivity (rho) decreases from almost insulation at T = 0 to a minimum at about T = 100 K. rho then increases more than linearly with T (similar to T (3/2)) in the region 100 Cu(I) + Cu(III) is responsible for the strong absorption in the visible spectrum of La2CuO4. The down-shift of spectral density with doping (x) in La2-x Sr (x) CuO4 depends on the appearance of Cu(III) sites which makes optical as well as thermal one-electron exchange transitions possible with lower energy. Disproportionation occurs spontaneously for x > 0.06, opening up for electron pair formation. Configuration interaction between two-electron states of low chemical potential, but strong vibrational coupling, gives rise to the superconductor and pseudogaps. Data from photo-induced conductivity and absorption spectra are used in the simulation, which gives results in good agreement with experiments. Possible explanations for Raman and MIR absorption suggest themselves. |
| وصف الملف: | electronic |
| URL الوصول: | https://research.chalmers.se/publication/248202 http://publications.lib.chalmers.se/records/fulltext/248202/local_248202.pdf |
| قاعدة البيانات: | SwePub |
| تدمد: | 15571947 15571939 |
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| DOI: | 10.1007/s10948-016-3666-0 |