We argue that the S=1/2 kagome antiferromagnet undergoes a quantum phase transition when the Dzyaloshinskii-Moriya coupling is increased. For D<Dc the system is in a moment-free phase and for D>Dc the system develops antiferromagnetic long-range order. The quantum critical point is found to be Dc≃0.1J using exact diagonalizations and finite-size scaling. This suggests that the kagome compound ZnCu3(OH)_6Cl_3$ may be in a quantum critical region controlled by this fixed point.
@article{arxiv.0806.0393,
title = {Quantum phase transition induced by Dzyaloshinskii-Moriya in the kagome antiferromagnet},
author = {O. Cepas and C. M. Fong and P. W. Leung and C. Lhuillier},
journal= {arXiv preprint arXiv:0806.0393},
year = {2009}
}
Comments
5 pages, 4 figures; v2: add. data included, show that D=0.1J is at a quantum critical point