EAGER: Braiding of Majorana Zero Modes in the Quantum Hall - Superconductor Hybrids

EAGER：量子霍尔中马约拉纳零模式的编织 - 超导混合体

基本信息

批准号：
1743907
负责人：
Gleb Finkelstein
金额：
$ 30万
依托单位：
Duke University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2020-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1743907&HistoricalAwards=false
关键词：
EAGER Braiding Majorana Zero Modes

项目摘要

Non-technical Abstract:Semiconductor electronics currently relies on the flow of electrons and holes, but other types of particle-like "excitations" can be artificially created and controlled. These excitations, which include so-called Majorana fermions and non-abelian anyons, have properties that protect them against external perturbations. As a result of this robustness, control over such "topological excitations" would revolutionize electronics and bring quantum computing closer to reality. Over the past few years, the condensed matter research community achieved dramatic progress in the practical implementation of topological excitations. It was indeed realized that they could be artificially created by inducing superconductivity into certain types of low-dimensional materials such as semiconducting nanowires. The PI proposes an alternative approach to create the topological excitations based graphene subject to high magnetic fields and coupled to superconducting electrodes. The individual topological excitations are connected by gateable links, allowing one to controllably couple and manipulate them. The planar nature of the host material should facilitate making multiple copies of these devices, enabling future scaling and integration with conventional electronics. The project strongly emphasizes mentoring and education: it involves two PhD students, and undergraduate and a high school student. High school students from the NC School of Science and Math will be recruited to participate in the laboratory activities and get a feel for physics research. This research will train the graduate and undergraduate students in the measurement and nanofabrication methods relevant for both industrial and academic careers.Technical Abstract:Working with Josephson junctions based on graphene contacted by type II superconductor, the principal investigator's group reported last year on the first observation of supercurrent through a two-dimensional region in the regime of the quantum Hall effect. This result proves the capability to coherently couple the superconductor electrodes to the quantum Hall edge states. It allows the principal investigator's group to approach superconductor-quantum Hall interfaces with more complex geometries, which are expected to host Majorana fermions. The specific goals are the superconducting electrodes in a shape of quasi-1D "trenches" etched in a quantum Hall mesa, with the edge states counter-propagating on the opposite sides of the contact. It has been predicted that in the spin-polarized quantum Hall regime (for example, at the filling factor equal to one), Majorana zero modes are formed at the ends of the trenches. Realizing these devices requires fundamental understanding of the coupling between the quantum Hall states and superconductor, as well as the development of fabrication techniques to design extremely clean interfaces between the superconducting contacts and the quantum Hall host material. Graphene has much to offer in that regard: a tunable band-structure and a remarkable electronic quality, which results in the appearance of the spin-polarized quantum Hall states at relatively low magnetic fields. Once formed, the Majoranas zero modes could be connected by gateable edge-state links, allowing one to controllably fuse (hybridize) them. Multiple copies of these excitations could be fabricated on the same mesa, enabling their braiding. The planar nature of the host material should facilitate making multiple copies of these devices, enabling future scaling and integration with conventional read-out electronics. Last but not least, the measurements are expected to reveal the fascinating physics of non-abelian anyons, which have properties distinctly different from any conventional quasiparticles. These topological excitations are relevant to a whole class of hybrid topological devices and could lead to breakthroughs that help make quantum computing a reality.

非技术摘要：半导体电子学目前依赖于电子和空穴的流动，但其他类型的粒子状“激发”可以人为地创建和控制。这些激发包括所谓的马约拉纳费米子和非阿贝尔任意子，具有保护它们免受外部扰动的特性。由于这种鲁棒性，对这种“拓扑激发”的控制将彻底改变电子学并使量子计算更接近现实。在过去的几年里，凝聚态研究界在拓扑激发的实际应用方面取得了巨大的进展。人们确实意识到，可以通过将超导性引入某些类型的低维材料（例如半导体纳米线）来人工制造它们。 PI 提出了一种替代方法来创建基于拓扑激发的石墨烯，使其受到高磁场的影响并与超导电极耦合。各个拓扑激励通过可门控链路连接，允许人们可控地耦合和操纵它们。主体材料的平面性质应该有助于制造这些设备的多个副本，从而实现未来的扩展以及与传统电子设备的集成。该项目非常强调指导和教育：它涉及两名博士生、一名本科生和一名高中生。来自北卡罗来纳州科学与数学学院的高中生将被招募参加实验室活动并感受物理研究。这项研究将为研究生和本科生提供与工业和学术生涯相关的测量和纳米制造方法的培训。技术摘要：主要研究人员小组去年报告了第一个观察结果，该研究基于与 II 型超导体接触的石墨烯的约瑟夫森结超电流通过量子霍尔效应范围内的二维区域。这一结果证明了超导电极与量子霍尔边缘态相干耦合的能力。它使首席研究员的团队能够接近具有更复杂几何形状的超导体-量子霍尔界面，预计这些界面将容纳马约拉纳费米子。具体目标是在量子霍尔台面上蚀刻出准一维“沟槽”形状的超导电极，边缘态在接触的相对侧反向传播。据预测，在自旋极化量子霍尔体系中（例如，在填充因子等于1时），马约拉纳零模式在沟槽的末端形成。实现这些器件需要对量子霍尔态和超导体之间的耦合有基本的了解，以及开发制造技术来设计超导触点和量子霍尔主体材料之间极其干净的界面。石墨烯在这方面有很多优势：可调谐的能带结构和卓越的电子质量，这导致在相对较低的磁场下出现自旋极化量子霍尔态。一旦形成，马约拉纳零模式可以通过可门控的边缘状态链路连接，从而允许人们可控地融合（混合）它们。这些激励的多个副本可以在同一台面上制造，从而实现编织。主体材料的平面性质应有助于制造这些设备的多个副本，从而实现未来的扩展以及与传统读出电子设备的集成。最后但并非最不重要的一点是，这些测量预计将揭示非阿贝尔任意子的迷人物理学，其特性与任何传统的准粒子明显不同。这些拓扑激发与一整类混合拓扑器件相关，并可能带来突破，帮助量子计算成为现实。

项目成果

期刊论文数量（7）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Quantum Hall–based superconducting interference device

基于量子霍尔的超导干涉装置

DOI：
10.1126/sciadv.aaw8693
发表时间：
2019-01-17
期刊：
Science Advances
影响因子：
13.6
作者：
A. Seredinski;A. Draelos;E. Arnault;M. Wei;Hengming Li;T. Fleming;Kenji Watanabe;T. Taniguchi;F. Amet;G. Finkelstein
通讯作者：
G. Finkelstein

Chiral quasiparticle tunneling between quantum Hall edges in proximity with a superconductor

靠近超导体的量子霍尔边缘之间的手性准粒子隧道效应

DOI：
10.1103/physrevb.100.121403
发表时间：
2019-09
期刊：
Physical Review B
影响因子：
3.7
作者：
Wei, M. T.;Draelos, A. W.;Seredinski, A.;Ke, C. T.;Li, H.;Mehta, Y.;Watanabe, K.;Taniguchi, T.;Yamamoto, M.;Tarucha, S.;et al
通讯作者：
et al

Supercurrent Flow in Multiterminal Graphene Josephson Junctions

多端石墨烯约瑟夫森结中的超电流

DOI：
10.1021/acs.nanolett.8b04330
发表时间：
2019-01
期刊：
Nano Letters
影响因子：
10.8
作者：
Draelos, Anne W.;Wei, Ming;Seredinski, Andrew;Li, Hengming;Mehta, Yash;Watanabe, Kenji;Taniguchi, Takashi;Borzenets, Ivan V.;Amet, François;Finkelstein, Gleb
通讯作者：
Finkelstein, Gleb

Interference of chiral Andreev edge states

手性安德烈夫边缘态的干涉

DOI：
10.1038/s41567-020-0898-5
发表时间：
2019-07-03
期刊：
Nature Physics
影响因子：
19.6
作者：
Lingfei Zhao;E. Arnault;A. Bondarev;A. Seredinski;T. Larson;A. Draelos;Hengming Li;Kenji Watanabe;T. Taniguchi;F. Amet;H. Baranger;G. Finkelstein
通讯作者：
G. Finkelstein

Subkelvin lateral thermal transport in diffusive graphene

扩散石墨烯中的亚开尔文横向热传输

DOI：
10.1103/physrevb.99.125427
发表时间：
2018-12-31
期刊：
Physical Review B
影响因子：
3.7
作者：
A. Draelos;A. Silverman;B. Eniwaye;E. Arnault;C. Ke;M. Wei;I. Vlassiouk;I. Borzenets;F. Amet;G. Finkelstein
通讯作者：
G. Finkelstein