Effect of four-spin interaction on magnetic excitation in ladder and 2D insulating cuprates
Effect of four-spin interaction on magnetic excitation in ladder and 2D insulating cuprates
复制标题
四自旋相互作用对梯形和二维绝缘铜氧化物中磁激励的影响
DOI：
10.1016/s0022-3697(00)00144-x
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发表时间：
2001
影响因子：
4
通讯作者：
S. Maekawa
中科院分区：
文献类型：
--
作者：
Y. Mizuno;T. Tohyama;S. Maekawa
研究了循环四自旋相互作用对两腿梯和二维绝缘铜酸盐中磁激发谱的影响。采用数值精确对角化方法计算了动态自旋相关函数S（q,ω）。对于阶梯系统，通过引入Jcyc，我们发现自旋波沿动量q =(0, π)到（π/2,π）的色散趋于平坦。这一特征与近年来非弹性中子散射测量的实验结果一致。对于二维系统，我们发现jcycy有效地减少了最近邻（NN） Cu自旋之间的磁相互作用约20%。此外，还发现沿磁区边界q =(π,0)到（π/2,π/2）的色散具有有限的宽度。这种行为可以通过考虑jcyc在下一个NN Cu自旋之间有效地给出铁磁对角相互作用来理解。为了验证Jcyc的效果，需要对二维铜酸盐进行高能区域的非弹性中子散射实验。
We investigate the effect of the cyclic four-spin interaction Jcycon the magnetic excitation spectra in two-leg ladder and two-dimensional (2D) insulating cuprates. The dynamical spin-correlation function S(q,ω) is calculated by using the numerically exact diagonalization method. For the ladder system, we find that the dispersion of spin wave along momentum q =(0, π ) to (π/2,π) flattens by introducing Jcyc. This feature is consistent with the experimental results of recent inelastic neutron-scattering measurement. For the 2D system, we find that the Jcycreduces effectively the magnetic interactions between nearest-neighbor (NN) Cu spins by about 20%. Moreover, it is found that the dispersion along the magnetic zone boundary from q =( π ,0) to (π/2,π/2) has a finite width. This behavior can be understood by considering that the Jcycgives effectively a ferromagnetic diagonal interaction between next NN Cu spins. In order to verify the effect of Jcyc, the inelastic neutron-scattering experiment at high-energy region will be highly desirable for 2D cuprates.