Mid-infrared absorption in YBa2Cu3O6: Failure of spin-wave theory in undoped cuprates?
Preprint
- 27 April 1999
Abstract
The optical conductivity sigma (omega) of undoped YBa2Cu3O6 is studied in detail in the mid-infrared range. Substitutions on all but the Ba site are used to identify the prominent absorption processes at 2800 and 3800 cm^-1. Experimental evidence for bimagnon-plus-phonon absorption is collected. A more critical analysis of the lineshape and the spectral weight reveals the limits of this approach. Although phonon-2-magnon multiple scattering seems to reproduce the lineshape, the necessary coupling is unrealistically large. The strong increase of high frequency spectral weight with increasing temperature makes the failure of spin-wave theory even more evident.Keywords
All Related Versions
- Version 1, 1999-04-27, ArXiv
- Published version: Physical Review B, 62 (18), 12422.
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