Effective-medium approximation for the dynamical excitations of percolating antiferromagnets.
Effective-medium approximation for the dynamical excitations of percolating antiferromagnets.
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渗透反铁磁体动态激发的有效介质近似。
DOI：
10.1103/physrevb.39.9353
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Orbach
中科院分区：
文献类型：
--
作者：
Polatsek;Entin;Orbach
在有效介质近似下研究了稀释反铁磁体的动态激发谱。最近的结果基于这种近似进行了修订和中子散射的结构因子进行了详细的分析和数值评估。该谱揭示了在交叉频率ω c <$（p-pc）3/2处从扩展激发到局域激发的急剧交叉，其中p是渗滤浓度，pc是稀释反铁磁体的渗滤阈值。结果进行了比较，最近的中子衍射实验和分形子的标度模型。
The dynamical-excitation spectrum of a diluted antiferromagnet is studied in the effective-medium approximation. Recent results based upon this approximation are revised and a detailed analysis of the structure factor for neutron scattering is carried out and evaluated numerically. The spectrum reveals a sharp crossover from extended to localized excitations at a crossover frequency, ω c∝(p-p c) 3/2, where p is the percolation concentration and p c is the percolation threshold of the diluted antiferromagnet. The results are compared with recent neutron-diffraction experiments and with the scaling model for fractons.