量子点复合水凝胶及其应用外文翻译资料

Providing a spin-free host material in the development of quantum information technology has made silicon a very interesting and desirable material for qubit design. Much of the work and experimental progress has focused on isolated phosphorous atoms. In this article, we report on the exploration of Ni–Si clusters that are atomically manufactured via self-assembly from the bottom-up and behave as isolated quantum dots. These small quantum dot structures are probed at the atomic-scale with scanning tunneling microscopy and spectroscopy, revealing robust resonance through discrete quantized energy levels within the Ni–Si clusters. The resonance energy is reproducible and the peak spacing of the quantum dot structures increases as the number of atoms in the cluster decrease. Probing these quantum dot structures on degenerately doped silicon results in the observation of negative differential resistance in both I–V and dI/dV spectra. At higher surface coverage of nickel, a well-known radic;19 surface modification is observed and is essentially a tightly packed array of the clusters. Spatial conductance maps reveal variations in the local density of states that suggest the clusters are influencing the electronic properties of their neighbors. All of these results are extremely encouraging towards the utilization of metal modified silicon surfaces to advance or complement existing quantum information technology.

There has been significant progress toward the utilization of an electronrsquo;s spin for the development of quantum bits (qubits) poised to revolutionize modern computers, where the orientation of the spin serves as the basis for “0” and “1” logic operations. A major challenge is scaling this technology toward meaningful quantum computation requiring the entanglement of multiple qubits with coherence times long enough for calculations to occur and simultaneously be measured. Not surprisingly, materials are at the heart of this challenge, from the fabrication of the qubits to how the electron or nuclear spin interacts with the host material. One of the most advantageous platforms has been developing solid-state qubit architectures using traditional semiconductors, where an entire industrial infrastructure exists and hybridization with conventional technology would be greatly beneficial. A predominant approach has been developing qubit systems with quantum dots using III–V semiconductor heterostructures, where the lowered dimensionality is utilized for quantum confinement. Significant advances have been made toward addressing the spin in these quantum dot structures that include fast optical control and all-electrical measurements. However, the qubit interaction with the nuclear spins, inherent in the III–V materials, reduces the coherence time and presents a significant challenge. Alternatively, group IV semiconductors are quite attractive for qubit design because they can provide a spin-free environment, where electron spin coherence times have been measured on the order of seconds.

The utilization of silicon, a zero nuclear spin material, has been the focus of several proposals as an optimal material for qubit design. Kane et al. first described using the nuclear spins of phosphorous dopants arranged as an array within a silicon lattice for the development of a quantum computer. Several experimental efforts are underway to fully develop qubit and quantum technologies based on phosphorous dopants. A key to these efforts has been the utilization of scanning tunneling microscopy (STM) to both fabricate and characterize the unique placement of single phosphorous donors on both silicon and germanium surfaces. Most impressive has been the placement of isolated phosphorous dopants within electronic contacts that can be macroscopically addressed. Although it is not practical to utilize the STM for large-scale qubit fabrication, it has proven to be a powerful tool for the development of proof-of-principle devices and local characterization of quantum structures and phenomena at the atomic-scale.

Rather than fabricating individual quantum structures with the STM, we are interested in exploring large-scale atomic manufacturing of alternative quantum dot structures that self-assemble, consist of only a handful of atoms, and are integrated with a semiconductor substrate. The goal is to find a suitable “bottom-up” approach that is scalable for qubit design. Complimentary to STM fabrication of individual quantum structures between electrical contacts, we envision scalability by controlling the density of self-assembled quantum dots over an entire surface. This would allow for the patterning of contacts anywhere on the surface and, with optimization, result in the desired density of quantum dots (from one to many) to exist between the contacts. There has been significant research in the area of metal functionalization of silicon surfaces in the context of thin film growth, metal silicides, and the modification of surface reconstructions. Guided by these efforts, we investigated the submonolayer deposition of Ni on Si(111). At these low coverages, the surface reconstruction is modified and two distinct Ni–Si clusters emerge that consist of either a “1thinsp;times;thinsp;1” or “radic;19” quantum dot structure consisting of an ordered grouping of Ni and Si atoms. Here, we report the investigation of quantum dot behavior and electron confinement in these Ni–Si atomic clusters. Utilizing scanning tunneling spectroscopy (STS), we observe resonant tunneling through quantized levels at reproducible energies within the clusters and a largerpeak spacing for the smaller clusters, as anticipated for shrinking dimensions. Furthermore, by degenerately doping (n-type) the host substrate, we can give rise to negative differential resistance (NDR) observed at negative sample bias. Finally, at higher surface coverage, the larger clusters form a uniform metal-silicon reconstruction across the surface with a complex electronic l

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在量子信息技术的发展中提供一种自旋的主机材料，使硅成为一种非常有趣和理想的材料，用于量子位设计。大部分的工作和实验进展都集中在孤立的磷原子上。在这篇文章中，我们报告了从自底向上的自组装到原子制造的nisi集群的探索，并表现为孤立的量子点。这些小的量子点结构通过扫描隧道显微镜和光谱学，在原子尺度上被探测到，通过在nisi簇中离散的量子化能级，揭示了强大的共振。共振能是可再生的，当星团中的原子数量减少时，量子点结构的峰值间距会增加。研究这些量子点结构在简并掺杂硅的结果中，在i - v和dI / dV光谱中观察到负微分电阻。在镍的表面覆盖率更高,一个著名的radic;19表面改性是观察和本质上是一个紧密数组的集群。空间电导图揭示了区域密度的变化，这表明星系团正在影响他们邻居的电子属性。所有这些结果对于利用金属改性硅表面来推进或补充现有的量子信息技术都是非常令人鼓舞的。

电子自旋对量子比特(量子位)的发展已经取得了重大的进展，这将使现代计算机发生革命性的变化，而旋转的方向是“0”和“1”逻辑运算的基础。一个主要的挑战是将这项技术扩展到有意义的量子计算，需要有多个量子位的纠缠，时间足够长，足够计算，同时测量。不足为奇的是，材料是这个挑战的核心，从量子化到电子或核自旋与宿主物质的相互作用。其中一个最有利的平台是使用传统半导体开发固态qubit体系结构，在那里，整个工业基础设施存在，与传统技术进行杂交将大有裨益。一种主要的方法是利用iii - v半导体异质结构，在量子点上开发量子点系统，在此基础上，降低的维度被用于量子约束。在这些量子点结构中，包括快速光学控制和全电测量的旋转，已经取得了重大进展。但是，与核自旋的量子位相互作用，在iii - v材料中，降低了相干时间，并提出了一个重大的挑战。或者，第四组半导体对量子位设计相当有吸引力，因为他们可以提供一个自旋自由的环境，其中电子自旋相干时间是按秒的顺序来测量的。

硅的利用，零核自旋材料，已经成为几个建议的焦点，作为qubit设计的最佳材料。凯恩等人首先描述了在硅晶格层中为量子计算机的发展而排列的磷掺杂剂的核自旋。目前正在进行一些实验，以充分开发基于磷的量子技术和量子技术。这些努力的一个关键是利用扫描隧道显微镜(STM)来制造和描述单个磷的在硅和锗表面的独特位置。最令人印象深刻的是在电子接触中放置分离的磷掺杂物可以被宏观地处理。虽然利用STM来进行大规模量子比特制造是不实际的，但它已经被证明是一种强大的工具，可以在原子尺度上对量子结构和量子结构和现象的特性进行研究。

我们并不是在用STM制造单个的量子结构，而是想探索大型的原子制造量子点结构，这些量子点结构是自组装的，只有少量的原子，并与半导体基板集成。目标是找到适合于qubit设计的可伸缩的“自底向上”方法。我们通过控制在整个表面的自组装量子点密度来设想可扩展性。这将允许在表面上的任何地方的接触模式，并通过优化，导致在接触之间存在所需的量子点密度(从一个到多个)。摘要在薄膜生长、金属硅化和表面重建等方面，对硅表面的金属功能化领域进行了大量的研究。在这些努力的指导下，我们研究了Ni(111)的次单层沉积。修改这些低保险,表面重建和两个截然不同的Ni-Si集群出现,由“1times;1”或“radic;19”量子点结构有序的倪分组和Si原子组成的。在这里，我们报告了在这些nisi原子簇中量子点行为和电子约束的研究。利用扫描隧道光谱学(STS)，我们观察到在星团内的可再生能量的量子化水平的共振隧穿，以及较小的星系团的最大间距，如预期的收缩尺寸。此外，通过非均匀掺杂(n型)的主底物，我们可以产生负差压差的负微分电阻(NDR)。最后，在较高的表面覆盖范围内，较大的星系团在表面形成均匀的金属硅重建，具有复杂的电子环境。本研究提出了一种模型系统，用于在两种不同尺寸之间可调谐的量子点设计的原子量子点的大规模分布，以及可复制的量子化能级，并可用于展示NDR。

在一个Si(111)基板上的Ni被蒸发到一个Si(111)上，以观察原子的nisi簇的初始形成，正如图1的STM图像所示。地形的STM图像,得到的样品温度55 K,我们观察区域的清洁Si(111)7times;7表面重建是镇定,从而验证submonolayer覆盖。大多数图像显示的是表面的Ni修改。在低覆盖率中，较小的7个原子集群是最普遍的。这些星系团在地形上以小的“甜甜圈”的形式出现，就像图中所示的地形图像一样，在放大的嵌套中被黄色虚线圈突出显示。我们把这些归为“1times;1”集群采用文学的命名,倪修改结果1times;1点的底层硅原子。1times;1集群的结构模型示意图绘制在图1 b。仔细观察这些STM图像，在地形图像中会出现更大的星系团。STM对国家的局部密度(LDOS)很敏感，而在这种特殊的样本偏差中，较大的集群中的电子差异导致的集群看起来有点抑郁，进入了第一层Si。这些集群被归类为“radic;19”集群和突出显示蓝色的圆圈内的放大图1 b的插图。我们采用了从文学术语在更高的表面覆盖这些大型集群顺序而在表面产生报道radic;19 Ni-Si表面重建。图1的示意图，显示了空间更大的量子点簇。

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