Symmetry-Driven Novel Kondo Effect in a Molecule
Symmetry-Driven Novel Kondo Effect in a Molecule
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DOI：
10.1103/physrevlett.109.086602
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发表时间：
2012-08-22
影响因子：
8.6
通讯作者：
Kawai, Maki
中科院分区：
文献类型：
--
作者：
Minamitani, Emi;Tsukahara, Noriyuki;Kawai, Maki
采用密度泛函理论和扫描隧道显微镜下的重整化群计算相结合的方法，研究了铁酞菁(FePc)在Au(111)面上吸附引起的Kondo效应。我们发现，对于Au(111)面上的单个FePc分子，通过与衬底的局域配位来调节配位场的对称性，实现了一种新颖的近藤效应。对于顶层构型的FePc，在Fe2+离子周围保持四重对称性，轨道自由度保持不变，导致自旋+轨道SU(4)Kondo效应。相反，桥构型中对称性的降低冻结了轨道的自由度，导致了自旋SU(2)近藤效应。这些结果为通过调节局域对称性来操纵多体现象提供了一个新的例子。
The Kondo effect caused by the adsorption of iron phthalocyanine (FePc) on Au(111) was investigated by the combination of density functional theory and a numerical renormalization group calculation with scanning tunneling microscopy. We found that a novel Kondo effect is realized for a single FePc molecule on Au(111) by tuning the symmetry of the ligand field through the local coordination to the substrate. For FePc in the on top configuration where fourfold symmetry around the Fe2+ ion is held, the orbital degrees of freedom survive, resulting in the spin+orbital SU(4) Kondo effect. In contrast, the reduced symmetry in the bridge configuration freezes the orbital degrees of freedom, leading to the spin SU(2) Kondo effect. These results provide a novel example to manipulate the many-body phenomena by tuning the local symmetry.