2024-03-29T07:23:13Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/301172022-11-17T02:08:08Zhdl_2115_20039hdl_2115_116Low-energy structure of the homometallic intertwining double-chain ferrimagnets A3Cu3(PO4)4 (A=Ca,Sr,Pb)Yamamoto, ShojiOhara, Jun420Motivated by the homometallic intertwining double-chain ferrimagnets A3Cu3(PO4)4 (A=Ca,Sr,Pb), we investigate the low-energy structure of their model Hamiltonian H = Σ n[J1(Sn:1+Sn:3)+J2(Sn+1:1+Sn−1:3)]・Sn:2, where Sn:l stands for the Cu2+ ion spin labeled l in the nth trimer unit, with particular emphasis on the range of bond alternation 0<J2/J1<1. Although the spin-wave theory, whether up to O(S1) or up to O(S0), claims that there exists a flatband in the excitation spectrum regardless of bond alternation, a perturbational treatment, as well as the exact diagonalization of the Hamiltonian, reveals its weak but nonvanishing momentum dispersion unless J2=J1 or J2=0. Quantum Monte Carlo calculations of the static structure factor further convince us of the low-lying excitation mechanism, elucidating similarities and differences between the present system and alternating-spin linear-chain ferrimagnets.American Physical SocietyJournal Articleapplication/pdfhttp://hdl.handle.net/2115/30117https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/30117/1/PRB76-01.pdf0163-18291095-3795Physical Review B7610144092007-07enginfo:doi/10.1103/PhysRevB.76.014409Copyright © 2007 American Physical Societypublisher