Chirality and Z2 vortices in a Heisenberg spin model on the kagome lattice

The phase diagram of the classical J1–J2 model on the kagome lattice is investigated by using extensive Monte Carlo simulations. In a realistic range of parameters, this model has a low-temperature chiral-ordered phase without long-range spin order. We show that the critical transition marking the destruction of the chiral order is preempted by the first-order proliferation of Z2 point defects. The core energy of these vortices appears to vanish when approaching the T=0 phase boundary, where both Z2 defects and gapless magnons contribute to disordering the system at very low temperatures. This situation might be typical of a large class of frustrated magnets. Possible relevance for real materials is also discussed.


Published in:
Physical Review B, 77, 17
Year:
2008
ISSN:
1550-235X
Laboratories:




 Record created 2011-05-11, last modified 2018-03-17

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