2007/09/24 by Fa Wang, Ashvin Vishwanath · 1 citation
Physics and Astronomy · #cond-mat.str-el #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevlett.100.077201
published as Phys. Rev. Lett. 100, 077201 (2008) · 5 pages, 4 figures
arxiv created 2007/09/24 · arxiv updated 2009/12/01
Coupling between spin and lattice degrees of freedom are important in geometrically frustrated magnets where they can lead to degeneracy lifting and novel orders. We show that moderate spin-lattice couplings in triangular and Kagome antiferromagnets can induce complex colinear magnetic orders. When classical Heisenberg spins on the triangular lattice are coupled to Einstein phonons, a rich variety of phases emerge, including the experimentally observed four sublattice state and the five sublattice 1/5th plateau state seen in the magneto-electric material CuFeO2. In addition we predict magnetization plateaus at 1/3, 3/7, 1/2, 3/5 and 5/7 at these couplings. Strong spin-lattice couplings induce a striped colinear state, seen in α-NaFeO2 and MnBr2. On the Kagome lattice, moderate spin-lattice couplings induce colinear order, but an extensive degeneracy remains.