Towards artificial Kondo nano-lattice structures

迈向人造近藤纳米晶格结构

• 批准号: 427676771
• 负责人: Professor Dr. Michael Huth
• 金额: --
• 依托单位: Physikalisches Institut
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/427676771?language=en
• 关键词: Towards; artificial; Kondo; nano; lattice

The Kondo effect is a prime example for the physics of correlated electron systems. In general terms, it is the result of the screening of a localized degeneracy coupled to a bath of fermions. In the narrower sense, the Kondo effect involves the formation of a spin singlet below a characteristic Kondo temperature if a magnetic impurity is embedded in a system of conduction electrons.An important open question relates to the nature of the characteristic length scale associated with the Kondo effect. This characteristic length scale or Kondo screening length can be estimated from the electronic energy gain associated with the singlet formation and the Fermi velocity of the conduction electrons. Theoretical estimates find it to be in the range from 10 to 1000 nm for metallic Kondo systems.In this project first steps will be taken towards a systematic study of the nature of the Kondo screening cloud and its associated length scale in nanoscale metallic Kondo systems. For this two complementary approaches are followed.In one approach, metallic Kondo single electron transistors (SET) based on the Kondo system Platinum-Chromium will be fabricated by combining area-selective atomic layer deposition and focused electron beam induced deposition (FEBID). The temperature- dependent low-temperature current-voltage characteristics of the metallic Kondo SETs will shed light on the question whether the formation of a Kondo screening cloud is subject to finite-size renormalization effects.The second approach uses nano-granular metals prepared by FEBID in which metallic nano-grains are dopend with magnetic impurities such as to form the novel material class of granular Kondo metals. Tunneling between the nano-grains may be expected to become coherent at low temperatures and for sufficiently large tunneling rates, such that a coherent, granular Fermi liquid is formed, as has been found in conventional nano- granular metal structures in the strong tunnel coupling regime. Of major scientific relevance will be to understand what the similarities and differences are in comparison with the coherent heavy fermion state known from a large class of intermetallic Ce, Yb or U compounds.

Kondo效应是相关电子系统物理学的一个主要例子。总的来说，这是筛选局部变性与葬礼浴的结果。从较窄的意义上讲，如果将磁性杂质嵌入到传导电子系统中，则近托效应涉及在特征性围绕温度下方的旋转单线形成。该特征长度尺度或围质筛选长度可以从与单线形成和传导电子的费米速度相关的电子能量增益估计。理论估计值发现金属近关系系统的范围从10到1000 nm。在该项目中，将采取第一步，朝着对近托筛选云的性质及其相关的长度尺度的系统研究。在一种方法中，在一种方法中，将通过结合面积选择性原子层沉积和聚焦的电子束诱导的沉积（Febid）来制造基于Kondo System Platinum-chromium的金属近代单电子晶体管（SET）。金属近代集的依赖温度依赖的低温电流特性将揭示一个问题，即昆多筛选云的形成是否受到有限尺寸的重新分配效果的影响。第二种方法使用纳米颗粒金属在febid中制备的纳米颗粒金属，在金属纳米元素中以磁性启发性地构成了小说的材料。在低温和足够大的隧道速率中，纳米粒之间的隧道可能会变得连贯，从而形成相干的颗粒状费米液体，就像在强隧道偶联方案中常规的纳米颗粒金属结构中发现的那样。主要的科学相关性将是了解与从一大型的金属间CE，YB或U化合物中众所周知的连贯的繁重费米态相比，相似之处和差异是什么。