Abstract
The spin dynamics of coupled spin-$\frac{1}{2}$ antiferromagnetic Heisenberg chains is predicted to exhibit a longitudinal mode at low energies and temperatures below the N\'eel temperature. This mode is a dimensional crossover effect and reveals the presence of a limited amount of long-range antiferromagnetic order coexisting with quantum fluctuations. In this paper the existence of such a mode is confirmed in the model material ${\mathrm{KCuF}}_{3}$ using polarized and unpolarized inelastic neutron scattering, and the longitudinal polarization of the mode is definitively established. The line shape is broadened, suggesting a reduced lifetime due to decay into spin waves. In addition, the data show evidence of continuum scattering with a lower edge greater than the longitudinal mode energy. A detailed comparison is made with theoretical predictions and experimental work on other model materials.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
