A tunable two-impurity Kondo system in an atomic point contact
A tunable two-impurity Kondo system in an atomic point contact
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DOI：
10.1038/nphys2076
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发表时间：
2011-11-01
期刊：
影响因子：
19.6
通讯作者：
Kern, Klaus
中科院分区：
文献类型：
--
作者：
Bork, Jakob;Zhang, Yong-hui;Kern, Klaus
两个磁原子，一个附着在扫描隧道显微镜的尖端，一个吸附在金属表面上，每个构成一个近藤系统，已被提出作为一个最简单的可能的系统潜在的量子临界行为。我们已经成功地实现了这一概念实验夹持之间的扫描隧道显微镜的尖端和金表面的钴二聚体。通过控制针尖-样品的距离，使我们能够以前所未有的精度调整两个钴原子之间的相互作用。电子输运测量这两个杂质近藤系统揭示了丰富的物理场景，这是由交叉从本地近藤屏蔽非本地单态形成由于反铁磁耦合作为分离的钴原子的函数。
Two magnetic atoms, one attached to the tip of a scanning tunnelling microscope and one adsorbed on a metal surface, each constituting a Kondo system, have been proposed as one of the simplest conceivable systems potentially exhibiting quantum critical behaviour. We have succeeded in implementing this concept experimentally for cobalt dimers clamped between a scanning tunnelling microscope tip and a gold surface. Control of the tip-sample distance with subpicometre resolution enables us to tune the interaction between the two cobalt atoms with unprecedented precision. Electronic transport measurements on this two-impurity Kondo system reveal a rich physical scenario, which is governed by a crossover from local Kondo screening to non-local singlet formation due to antiferromagnetic coupling as a function of separation of the cobalt atoms.