Abstract
The interplay of different scattering mechanisms can lead to novel effects in transport. We show theoretically that the interplay of weak impurity and umklapp scattering in spin-1/2 chains leads to a pronounced dip in the magnetic field dependence of the thermal conductivity at a magnetic field . In sufficiently clean samples the reduction in the magnetic contribution to heat transport can easily become larger than 50%, and the effect is predicted to exist even in samples with a large exchange coupling, , where the field-induced magnetization is small. Qualitatively, our theory might explain dips at observed in recent heat transport measurements on copper pyrazine dinitrate, but a fully quantitative description is not possible within our model.
- Received 20 November 2008
DOI:https://doi.org/10.1103/PhysRevB.79.064406
©2009 American Physical Society