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arXiv 1507.08772cond-mat.str-elquant-ph
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量子临界点下三维反铁磁体的杂质感生磁化

Impurity-induced magnetization in three dimensional antiferromagnet at quantum critical point

Yaroslav A. Kharkov, Ivan S. Terekhov, Oleg P. Sushkov

摘要:

我们考虑一个自旋为$S$的单一杂质嵌入在一个接近量子临界点(QCP)的三维反铁磁系统中,分离磁有序和无序相。从无序相出发,研究了杂质引起的自旋密度和交错磁化强度的空间分布。用两种方法(自洽玻恩近似和重整化群),我们发现自旋密度$\propto 1/r^3$和交错磁化强度$\propto 1/r$都有幂律衰减,并作了相应的对数修正。我们证明了在杂质位$r=0$的局域自旋在QCP处趋近于零。我们证明了在大$S$的半经典极限下,这个问题等价于完全可解的独立玻色子模型。我们的结果表明,在三维系统中存在的自旋-电荷分离的QCP附近。

英文摘要:

We consider a single impurity with spin $S$ embedded in a three-dimensional antiferromagnetic system which is close to the quantum critical point (QCP), separating magnetically ordered and disordered phases. Approaching the QCP from the disordered phase we study the spatial distribution of spin density and staggered magnetization induced by the impurity. Using two methods (self-consistent Born approximation and renormalization group) we found a power law decay of the spin density $\propto 1/r^3$, and of the staggered magnetization $\propto 1/r$ with relevant logarithmic corrections. We demonstrate that the local spin at the impurity site $r=0$ approaches to zero at the QCP. We show that in the semiclassical limit of large $S$ the problem is equivalent to the exactly solvable independent boson model. Our results demonstrate existence of spin-charge separation in the three dimensional systems in the vicinity of the QCP.

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。

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