Spin dynamics of the 2D spin 1/2 quantum antiferromagnet copper deuteroformate tetradeuterate (CFTD).
- Rønnow, HM
- McMorrow, DF
- Coldea, R
- Harrison, A
- Youngson, ID
- Perring, TG
- Aeppli, G
- Syljuåsen, O
- Lefmann, K
- Rischel, C
Publication date
July 2001
DOI Publisher
American Physical Society (APS) Journal
Physical Review LettersAbstract
The magnetic excitation spectrum in the two-dimensional (2D) S = 1/2 Heisenberg antiferromagnet copper deuteroformate tetradeuterate has been measured for temperatures up to T approximately J/2, where J = 6.31+/-0.02 meV is the 2D exchange coupling. For T<<J, a dispersion of the zone boundary energy is observed, which is attributed to a wave vector dependent quantum renormalization. At higher temperatures, spin-wavelike excitations persist, but are found to broaden and soften. By combining our data with numerical calculations, and with existing theoretical work, a consistent description of the behavior of the model system is found over the whole temperature interval investigated
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