Finite-Field Ground State of an S=1 Anisotropic Antiferromagnetic Chain(Low Dimensional Systems, Field-Induced Phase Transitions and Dynamics in Quantum Spin Systems)

概要

論文の詳細を見る
We investigate, using numerical methods, the finite-field ground-state properties of an S=1 anisotropic antiferromagnetic chain described by the Hamiltonian 〓=Σ_l{S^x_lS^x_<l+1>+S^y_lS^y_<l+1>+ΔS^z_lS^z_<l+1>}+DΣ_l(S^z_l)^2-HΣ_lS^z_l. It is found that the magnetization jump anomaly (a first-order phase transition) appears in the ground-state magnetization curve when Δ=5.0 and -1.50≲D≲1.05; in a certain region of D, the jump starts from a finite value of the magnetization m per spin. We also find that the a second-order phase transition between commensurate and incommensurate gapless phases takes place in the finite-field ground state. The critical point of this transition as well as the values of m at the onset and end of the magnetization jump is summarized in the m versus D phase diagram.
理論物理学刊行会の論文
2005-10-31