磁性非线性杂质的体局域态和表面局域态
Bulk and surface localized states on a magnetic nonlinear impurity
摘要：
我们研究了在磁场$B$作用于杂质位置时，位于一维链体或表面的单个磁性杂质上的局域模。强的现场非线性相互作用$U$的两个电子之间的相反的自旋在杂质网站，在这里建模为非线性本地项，和外部场的存在下诱导平行和反平行自旋束缚态之间的强相关性。我们发现，对于体中的杂质，对于任何给定的$U$和$B$值，局域矢量模式（具有上下自旋分量）总是可能的，而对于表面杂质，需要创建矢量模式的最小值，$U$和$B$。在这种情况下，最多可能有两个局域模，但其中只有一个是稳定的。表面的存在似乎使参数区域U~B中的体模不稳定，从而在参数空间中产生“禁带”区域，近似地以U=B+V和U=B-V为界。
英文摘要：
We study localized modes on a single magnetic impurity positioned in the bulk or at the surface of a one-dimensional chain, in the presence of a magnetic field $B$ acting at the impurity site. The strong on-site nonlinear interaction $U$ between two electrons of opposite spin at the impurity site, modelled here as a nonlinear local term, and the presence of the external field induce a strong correlation between parallel and anti-parallel spin bound states. We find that, for an impurity in the bulk, a localized vector mode (with up and down spin components) is always possible for any given value of $U$ and $B$, while for a surface impurity, a minimum value of both, $U$ and $B$ is needed to create a vector mode. In this case, up to two localized modes are possible, but only one of them is stable. The presence of the surface seems to destabilize the bulk mode in the parameter region U~B, creating a "forbidden strip" region in parameter space, bounded by U=B+V and U=B-V, approximately.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
