| Affiliation: | (1) Department of Physics, Hangzhou Teachers College, 310012 Hangzhou, P.R. China;(2) Instituto de Física da UFRGS, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, Brazil;(3) Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ, Brazil;(4) Department of Theoretical Physics, Research School of Physical Sciences and Engineering, and Centre for Mathematics and its Applications, Mathematical Sciences Institute, Australian National University, ACT 0200 Canberra, Australia |
| Abstract: | A spin-orbital chain with different Landé g factors and one-ion anisotropy is studied in the context of the thermodynamical Bethe ansatz. It is found that there exists a magnetization plateau resulting from the different Landé g factors. Detailed phase diagram in the presence of an external magnetic field is presented both numerically and analytically. For some values of the anisotropy, the four-component system undergoes five consecutive quantum phase transitions when the magnetic field varies. We also study the magnetization in various cases, especially its behaviors in the vicinity of the critical points. For the SU(4) spin-orbital model, explicit analytical expressions for the critical fields are derived, with excellent accuracy compared with numerics.Received: 8 January 2004, Published online: 8 June 2004PACS: 75.30.Kz Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.) - 71.27. + a Strongly correlated electron systems; heavy fermions - 75.10.Jm Quantized spin models |
