Consequences of Kondo exchange on quantum spins
Consequences of Kondo exchange on quantum spins
复制标题
DOI：
10.1016/j.susc.2014.07.009
复制
发表时间：
2014-12-01
期刊：
影响因子：
1.9
通讯作者：
Fernandez-Rossier, J.
中科院分区：
文献类型：
--
作者：
Delgado, F.;Hirjibehedin, C. F.;Fernandez-Rossier, J.
当单个量子自旋被放置在导电基板附近时，局域自旋通过近藤交换与附近的巡回传导电子耦合。在强耦合极限下，这可能会导致近藤效应——形成一个相关的、多体的单重态——以及在费米能量附近的态密度的重整化。然而，即使没有近藤筛选，近藤交换也会产生各种各样的其他现象。除了众所周知的g因子的重整化和有限的自旋退相干和弛豫时间外，近藤交换最近还发现了一个新发现的效应：单离子磁各向异性的重整化。在这里，我们通过对近藤交换效应的扰动处理，将这些明显不同的现象置于同等地位。在这种形式中，中心量为rho J，即费米能量rho的态密度与近田交换常数J的乘积。我们证明了微扰理论正确地描述了实验观察到的交换引起的单自旋激发能的位移，证明了近田交换可以用来调节单自旋的有效磁各向异性。(C) 2014 Elsevier B.V.版权所有
When individual quantum spins are placed in close proximity to conducting substrates, the localized spin is coupled to the nearby itinerant conduction electrons via Kondo exchange. In the strong coupling limit this can result in the Kondo effect - the formation of a correlated, many body singlet state - and a resulting renormalization of the density of states near the Fermi energy. However, even when Kondo screening does not occur, Kondo exchange can give rise to a wide variety of other phenomena. In addition to the well known renormalization of the g factor and the finite spin decoherence and relaxation times, Kondo exchange has recently been found to give rise to a newly discovered effect: the renormalization of the single ion magnetic anisotropy. Here we put these apparently different phenomena on equal footing by treating the effect of Kondo exchange perturbatively. In this formalism, the central quantity is rho J, the product of the density of states at the Fermi energy rho and the Kondo exchange constant J. We show that perturbation theory correctly describes the experimentally observed exchange induced shifts of the single spin excitation energies, demonstrating that Kondo exchange can be used to tune the effective magnetic anisotropy of a single spin. (C) 2014 Elsevier B.V. All rights reserved.