Destruction of valence-bond order in aS=12sawtooth chain with a Dzyaloshinskii-Moriya term

Zhihao Hao, Yuan Wan, Ioannis Rousochatzakis, Julia Wildeboer, A. Seidel, F. Mila, O. Tchernyshyov
2011 Physical Review B  
A small value of the spin gap in quantum antiferromagnets with strong frustration makes them susceptible to nominally small deviations from the ideal Heisenberg model. One of such perturbations, the anisotropic Dzyaloshinskii-Moriya interaction, is an important perturbation for the S=1/2 kagome antiferromagnet, one of the current candidates for a quantum-disordered ground state. We study the influence of the DM term in a related one-dimensional system, the sawtooth chain that has valence-bond
more » ... der in its ground state. Through a combination of analytical and numerical methods, we show that a relatively weak DM coupling, 0.115J, is sufficient to destroy the valence-bond order, close the spin gap, and turn the system into a Luttinger liquid with algebraic spin correlations. A similar mechanism may be at work in the kagome antiferromagnet.
doi:10.1103/physrevb.84.094452 fatcat:jwbfl2fcyvdgpet7y5ifxfmfhm