1999/12/31 by Weyls LiMing, W. Liming, Gregoire Misguich +4 · 7 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Physics of Superconductivity and Magnetism #Quantum many-body systems #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.62.6372
published as Phys. Rev B 62, 6372 (2000) · 6 pages (RevTex), 5 figures (eps). Published version
openalex publication_date 2000/09/01 · arxiv created 2000/12/06 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The phase diagram of the multiple-spin exchange model on the triangular lattice is studied using exact diagonalizations. The two-spin (J2) and four-spin (J4) exchanges have been taken into account for 12-, 16-, 19-, 21-, 24-, and 27-site samples in the parameter region J4=0--0.25 (for a fixed J2=1). It is found that the three-sublattice N'eel-ordered state built up by the pure two-spin exchange can be destroyed by the four-spin exchange, forming a spin-liquid state. The different data suggest that the phase diagram in this range of parameters exhibits two phases. The pure J2 phase is a three-sublattice N'eel-ordered phase; a small J4 drives it into a spin-liquid state with a spin gap filled of a large number of singlets. This spin-liquid phase is not of the same generic kind as the phase studied by Misguich et al. [Phys. Rev. B 60, 1064 (1999)]. It is observed on the finite-size samples that the spin-liquid phase, as the N'eel-ordered phase, exhibits a magnetization plateau at m=1/3, and for J4>0.15 a second plateau at m=1/2. These two plateaus are associated, respectively, with the semiclassical orderings uud and uuud.