1999/04/22 by Congjun Wu, Bin Chen, Xi Dai +2 · 3 citations
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum many-body systems #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.60.1057
published as Phys. Rev. B, 60 1057(1999) · 15 pages, 5 figures. Accepted by Phys. Rev. B
arxiv created 1999/04/22 · openalex publication_date 1999/07/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Schwinger-boson mean-field theory is applied to the quantum ferrimagnetic Heisenberg chain. There is a ferrimagnetic long-range order in the ground state. We observe two branches of the low-lying excitation and calculate the spin reduction, the gap of the antiferromagnetic branch, and the spin fluctuation at T=0 K. These results agree with the established numerical results quite well. At finite temperatures, the long-range order is destroyed because of the disappearance of the Bose condensation. The thermodynamic observables, such as the free energy, magnetic susceptibility, specific heat, and the spin correlation at T>0 K, are calculated. The T\ensuremathχuni has a minimum at intermediate temperatures and the spin-correlation length behaves as T^\ensuremath-1 at low temperatures. These qualitatively agree with the numerical results and the difference is small at low temperatures.