1999/01/27 by Pavel V. Shevchenko, P. V. Shevchenko, Valeri N. Kotov +2 · 2 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Organic and Molecular Conductors Research #Physics of Superconductivity and Magnetism #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.60.3305
published as Phys. Rev. B 60, 3305 (1999). · 18 pages, 13 figures
arxiv created 1999/01/27 · openalex publication_date 1999/08/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We have studied the low-energy excitation spectrum of a dimerized and frustrated antiferromagnetic Heisenberg chain. We use an analytic approach, based on a description of the excitations as triplets above a strong-coupling singlet ground state. The quasiparticle spectrum is calculated by treating the excitations as a dilute Bose gas with infinite on-site repulsion. Additional singlet (S=0) and triplet (S=1) modes are found as two-particle bound states of the elementary triplets. We have also calculated the contributions of the elementary and collective excitations into the spin structure factor. Our results are in excellent agreement with exact diagonalizations and dimer series expansions data as long as the dimerization parameter \ensuremathδ is not too small (\ensuremathδ>0.1), i.e., while the elementary triplets can be treated as localized objects.