With recent advances in the areas of nanostructure fabrication and molecular spintronics the idea of using single molecule magnets as building blocks for the next generation electronic devices becomes viable. A particular example represents a metal-organic complex in which organic ligands surround a rare-earth element or transition metal. Recently, it was explicitly shown that the relative position of the ligands with respect to each other can be reversibly changed by the external voltage without any need of the chemical modification of the sample. This opens a way of the electrical tuning of the Kondo effect in such metal-organic complexes. In this work, we present a detailed and systematic analysis of this effect in TbPc$_2$ from an ab initio perspective and compare the obtained results with the existing experimental data.
On-Surface Structural and Electronic Properties of Spontaneously Formed Tb$_2$Pc$_3$ Single Molecule Magnets
双酞菁铽（TbPc $_2$）单分子磁体（SMM）作为实现分子自旋电子学的一个范例体系，引起了人们的广泛关注。本文报道了TbPc $_2$前体在超高真空（UHV）中升华到Ag（111）表面上自发形成Tb $_2$ Pc $_3$物种。表面上的分子使用组合的扫描隧道（STM）和非接触原子力显微镜（nc-AFM）在5开尔文检查。密度泛函理论（DFT）计算支持的亚分子分辨率和高度相关的测量明确显示存在TbPc $_2$和Tb $_2$ Pc $_3$物种。通过化学分析独立地证实了在UHV条件下Tb $_2$ Pc $_3$物质的合成。高分辨率AFM成像使我们能够记录Tb $_2$ Pc $_3$和TbPc $_2$中最上面的Pc配体相对于下面的Ag（111）表面的取向。电子结构的测量揭示了一个近藤签名与温度$\sim$ 30 K的Tb $_2$ Pc $_3$物种，本地化的Pc配体叶的选择性外观。我们属性的近藤共振选择Tb $_2$ Pc $_3$分子的内部分子配体的取向上的存在。高分辨率AFM成像识别Tb $_2$ Pc $_3$分子之间的几何畸变，有和没有近藤效应，结构和电子差异之间的复杂相互作用的结果。
Iron impurities in gold and silver: Comparison of transport measurements to numerical renormalization group calculations exploiting non-Abelian symmetries
We investigate theoretically and experimentally the singlet-triplet Kondo effect induced by a magnetic field in a molecular junction. Temperature dependent conductance, $G(T)$, is calculated by the numerical renormalization group, showing a strong imprint of the relevant low energy scales, such as the Kondo temperature, exchange and singlet-triplet splitting. We demonstrate the stability of the singlet-triplet Kondo effect against weak spin anisotropy, modeled by an anisotropic exchange. Moderate spin anisotropy manifests itself by lowering the Kondo plateaus, causing the $G(T)$ to deviate fro…
We explore the physics of a spin-1/2 Heisenberg chain with Kondo interaction, $J_k$, to a two-dimensional electron gas. At weak $J_k$ the problem maps onto a Heisenberg chain locally coupled to a dissipative Ohmic bath. At the decoupled fixed point, the dissipation is a marginally relevant perturbation and drives long-range antiferromagnetic order along the chain. In the dynamical spin structure factor we observe a quadratic low-energy dispersion akin to Landau-damped Goldstone modes. At large $J_k$ Kondo screening dominates, and the spin correlations of the chain inherit the power law of the …
