Magnetic impurities coupled to quantum antiferromagnets in one dimension.
Magnetic impurities coupled to quantum antiferromagnets in one dimension.
复制标题
磁性杂质在一维中与量子反铁磁体耦合。
DOI：
--
复制
发表时间：
1994
期刊：
影响因子：
--
通讯作者：
P. Fulde
中科院分区：
文献类型：
--
作者：
J. Igarashi;T. Tonegawa;M. Kaburagi;P. Fulde
利用有限集团链的数值对角化方法，研究了一维海森堡模型反铁磁耦合的磁性杂质。通过计算结合能和关联函数，发现杂质周围都有一个局域单态。这适用于具有单个杂质、具有两个杂质以及形成晶格的杂质的系统。单重态的局部特征被发现是由其他杂质自旋的存在影响不大。一个小的有效相互作用之间的一对杂质自旋，它振荡依赖于杂质的距离。对于杂质晶格，如果耦合常数很小，能谱显示出一个间隙，该间隙被发现远小于每个杂质的结合能。对于较大的耦合常数，它增加到与结合能相同的数量级，表明局部单重态被打破以产生激发态。杂质晶格与铁磁耦合也进行了研究，并讨论了它们的连接的Haldle问题。
Magnetic impurities coupled antiferromagnetically to a one-dimensional Heisenberg model are studied by numerical diagonalization of chains of finite clusters. By calculating the binding energy and the correlation function, it is shown that a local singlet develops around each impurity. This holds true for systems with a single impurity, with two impurities, and for impurities forming a lattice. The local character of the singlet is found to be little affected by the presence of other impurity spins. A small effective interaction is found between a pair of impurity spins, which oscillates depending on impurity distances. For impurity lattices, the energy spectrum shows a gap which is found to be much smaller than the binding energy per impurity if the coupling constants are small. For larger coupling constants, it increases to the same order of magnitude as the binding energy, indicating that a local singlet is broken to create excited states. Impurity lattices with ferromagnetic couplings are also studied and their connection to the Haldane problem is discussed.