open access

https://hdl.handle.net/2115/30117

Low-energy structure of the homometallic intertwining double-chain ferrimagnets A3Cu3(PO4)4 (A=Ca,Sr,Pb)

英語

2007-07

American Physical Society

Physical Review B

76(1)

014409

Motivated 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.

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Copyright © 2007 American Physical Society

0163-1829

1095-3795