Poster Virtual Only
19 Oct 2023
The quantum spin chains exhibit various interesting phenomena in the magnetization process, for exmaple, the magnetization jump, plateau, and spin nematic liquid etc. The density matrix renormalization group analysis of the S=1 antiferromagnetic chain with the biquadratic exchange interaction indicated that the spin nematic liquid phase appears in the magnetization process[1]. It was also supported by the numerical diagonalization and the conformal field theory analysis[2,3]. In the present work, the magnetization processes of the S=3/2 and S=2 antiferromagnetic chains with the biquadratic exchange interaction are investigated using the numerical diagonalization of finite-size clusters. It is found that the magnetization jump appears just before the saturation magnetization, as well as the classical spin system. This behavior is different from the S=1 chain. In addition it is indicated that the magnetization process where each magnetization step is 2S appears for sufficiently large biquadratic interaction. Namely the three-magnon and four-magnon bound states are realized for the S=3/2 and S=2 chains, respectively. In the case of the S=1 chain, the spin nematic liquid phase appears in the two-magnon bound state. Thus in general it can be predicted that the 2S-magnon bound state would be induced by the biquadratic exchange interaction in the magnetization process of the spin-S antiferromagnetic chain. The phase diagrams with respect to the biquadratic interaction and the magnetization are also presented for S=3/2 and S=2 antiferromagnetic chains.References: [1]S. R. Manmana, A. M. Lauchli, F. H. L. Essler and F. Mila, Phys. Rev. B 83, 184433 (2011). [2]T. Sakai, AIP Advances 11, 015306 (2021). [3]T. Sakai, H. Nakano, R. Furuchi and K. Okamoto, J. Phys.: Conf. Ser. 2164, 012030 (2020).
