Extended String Order Parameter in the (S=1, 1/2) Mixed Spin Chain(Condensed matter: electronic structure and electrical, magnetic, and optical properties)

概要

論文の詳細を見る
We have found a set of order parameters that characterize the plateau state of the (S=1, 1/2) spin chain system. The order parameters are regarded as extensions of the string order parameter of the S=1 antiferromagnetic Heisenberg spin chain. The extension is made by mapping the S_z=1/2 (S_Z=-1/2) state of an S=1/2 spin onto the S_Z=0 (S_z=-1) state of an S=1 spin. Numerical data indicate that, when single-ion anisotropy D is introduced, all the order parameters decrease continuously and vanish in the large-D region. Our estimate of the critical value D_c for the phase transition agrees well with the phase boundary determined by a previous level spectroscopy analysis. We present estimates of three critical exponents that are associated with the order parameters. A scaling relation between the exponents holds well in the present system.
2007-08-15