Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA.
ACS Nano. 2010 Jul 27;4(7):3560-79. doi: 10.1021/nn100793s.
Molecular electronic devices currently serve as a platform for studying a variety of physical phenomena only accessible at the nanometer scale. One such phenomenon is the highly correlated electronic state responsible for the Kondo effect, manifested here as a "Kondo resonance" in the conductance. Because the Kondo effect results from strong electron-electron interactions, it is not captured by the usual quantum chemistry approaches traditionally applied to understand chemical electron transfer. In this review, we will discuss the origins and phenomenology of Kondo resonances observed in single-molecule devices, focusing primarily on the spin-1/2 Kondo state arising from a single unpaired electron. We explore the rich physical system of a single-molecule device, which offers a unique spectroscopic tool for investigating the interplay of emergent Kondo behavior and such properties as molecular orbital transitions and vibrational modes. We will additionally address more exotic systems, such as higher spin states in the Kondo regime, and we will review recent experimental advances in the ability to manipulate and exert control over these nanoscale devices.
分子电子器件目前是研究各种仅在纳米尺度上才有的物理现象的平台。其中一个现象是导致 Kondo 效应的高度关联电子态，在这里表现为电导中的“Kondo 共振”。由于 Kondo 效应源于强电子-电子相互作用，因此不能用传统上用于理解化学电子转移的通常量子化学方法来捕捉。在这篇综述中，我们将讨论在单分子器件中观察到的 Kondo 共振的起源和现象学，主要关注源于单个不成对电子的自旋 1/2 Kondo 态。我们探索了单分子器件这一丰富的物理系统，它为研究新兴的 Kondo 行为与分子轨道跃迁和振动模式等特性之间的相互作用提供了独特的光谱工具。我们还将讨论更奇特的系统，例如 Kondo 区中的更高自旋态，并回顾最近在操纵和控制这些纳米尺度器件方面的实验进展。
