Instability of Antiferromagnetic Magnons in Strong Fields
Abstract
We predict that spin waves in an ordered quantum antiferromagnet in a strong magnetic field become unstable with respect to spontaneous two-magnon decays. At zero temperature, the instability occurs between the threshold field H* and the saturation field Hc. As an example, we investigate the high-field dynamics of a Heisenberg antiferromagnet on a square lattice and show that the single-magnon branch of the spectrum disappears in most of the Brillouin zone.
- Publication:
-
Physical Review Letters
- Pub Date:
- May 1999
- DOI:
- 10.1103/PhysRevLett.82.4536
- arXiv:
- arXiv:cond-mat/9808100
- Bibcode:
- 1999PhRvL..82.4536Z
- Keywords:
-
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- RevTeX, 4 pages, 3 figures, accepted to PRL