Artificial Atoms

9732579卡斯特纳，这项建议中建议的研究涉及量子点和单电子晶体管的性质。这些量子点(“人造原子”)的性质与普通电子设备有很大的不同，需要进行基础研究，长期目标是将这些新结构转化为技术成熟的系统。这需要确定这些人造原子的能级和跃迁概率，这些人造原子的直径通常是普通原子大小的1000倍。基于人造原子原理的晶体管，即“单电子晶体管”(SET)，是下一代电子设备的目标。提出的研究集中在两个主题上，即1)人工原子中的电子如何与附近金属导线中的电子相互作用；2)强磁场中电子液滴的相变性质是什么。主题1)的耦合被认为是导致与近藤效应密切相关的行为，近藤效应是由于磁性杂质上的定域电子与宿主金属中的费米液体耦合而产生的。第二个主题涉及多电子液滴中磁场诱导的从单线态向铁磁态的相变。近藤问题将被研究为带有不同数量的电子的集合。相变将通过测量大于约1.7特斯拉临界场的磁场的磁化率来研究。本提案中建议的研究涉及量子点行为的基本问题，也称为人造原子。这类系统具有成为纳米级电子元件的巨大潜力，其中包括将成为下一代实用电子设备心脏的“单电子晶体管”(SETS)。量子点的性质与普通原子的性质是如此不同，以至于支配它们行为的基本物理还没有完全被理解。这样的理解将有助于更有效和更有控制地制造成套设备，并将其纳入实际技术设备。在这项提案中描述的研究中有两个问题受到攻击。它们都处理通过普通金属制成的导线流入和流出电视机的电流。***

9732579 Kastner The research suggested in this proposal concerns the properties of quantum dots and single electron transistors. The properties of these quantum dots ("artificial atoms") are sufficiently different from ordinary electronic devices to require fundamental studies with the long range goal of translating these novel structures into technologically mature systems. This requires determining the energy levels and transition probabilities for these artificial atoms whose diameters are typically 1000 times the size of ordinary atoms. Transistors based on the artificial atom principle, the "single electron transistors" (SET), are the goal of the next generation of electronic devices. The research proposed here focuses on two topics, namely 1) how do electrons in an artificial atom interact with those in nearby metallic leads and 2) what is the nature of the phase transitions of the electron droplets in high magnetic fields. The coupling of topic 1) is believed to be give rise to behaviors closely related to the Kondo effect, which results from the coupling of localized electrons on a magnetic impurity to the Fermi liquid in a host metal. The second topic relates to the magnetic field induced phase transition from a singlet state to the ferromagnetic state in droplets with many electrons. The Kondo problem will be investigated for SETs carrying various numbers of electrons. The phase transitions will be studied by measuring the magnetic susceptibilties for magnetic fields greater than the critical field of ca. 1.7 tesla. %%% Research suggested in this proposal deals with fundamental problems of the behavior of quantum dots, also called artificial atoms. Such systems have great potential to become nano-scale electronic components, including "single electron transistors" (SETs), which will become the heart of the next generation of practical electronic devices. The properties of quantum dots are so different from those of ordinary atoms that the fundamental physics governing their behavior is not yet fully understood. Such understanding will facilitate a more efficient and controlled manufacture of SETs and their incorporation in practical technological devices. Two problems are attacked in the research described in this proposal. Both of them deal with electric current flow into and out of the SETs via the leads made of ordinary metal. ***