In the highly frustrated pyrochlore magnet spins form a lattice of corner-sharing tetrahedra. We show that the tetrahedral "molecule" at the heart of this structure undergoes a Jahn-Teller distortion when lattice motion is coupled to the antiferromagnetism. We extend this analysis to the full pyrochlore lattice by means of Landau theory and argue that it should exhibit "spin-Peierls" phases with bond order but no spin order. We find a range of Néel phases, with collinear, coplanar, and noncoplanar order. While collinear Néel phases are easiest to generate microscopically, we also exhibit an interaction that gives rise to a coplanar state instead.
|Number of pages
|Physical Review B - Condensed Matter and Materials Physics
|Published - Aug 1 2002
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics