Electron tunneling spectroscopy of the novel pairing state in the 1-1-5 heavy fermions and possible topological Kondo insulator YbB12

1-1-5 重费米子和可能的拓扑近藤绝缘体 YbB12 中新型配对态的电子隧道光谱

• 批准号: 2003405
• 负责人: Wan Kyu Park
• 金额: $ 48.54万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-15 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003405&HistoricalAwards=false
• 关键词: Electron; tunneling; spectroscopy; novel; pairing

Non-technical Abstract: In this project, two important topics in condensed matter physics are studied using techniques that explore properties of electrons. First, transport of electricity without dissipation in a superconducting state is a fundamental topic addressed here by investigating a wide group of superconductors to determine the mechanism of superconductivity unambiguously. Second, the other half of this project focuses on topological insulators, a novel class of quantum matter harboring protected conducting states at their surfaces. How this novel property emerges is not yet understood when the interactions are strong. To tackle this unsolved problem, this project applies tunneling spectroscopy to multiple candidate materials in different forms and under hydrostatic pressure. Younger generation of scientists including graduate and undergraduate students are actively involved in this project by undertaking key experimental activities and trained to acquire professional skills such as written and verbal dissemination of their work. Outreach to underrepresented group is planned, as well as engagement in various activities focusing on elevating general public’s literacy in STEM fields.Technical Abstract: This project involves two forefront research topics in condensed matter physics: the pairing mechanism in the 1-1-5 family of heavy-fermion superconductors and the interplay between strong correlations and topology in correlated topological materials. Electron tunneling spectroscopy is employed to reveal their key spectroscopic properties that are essential for microscopic understanding of the underlying physics. Despite the widely accepted pairing mechanism involving spin fluctuations in heavy-fermion superconductors, key experimental signatures for the 1-1-5 family of heavy fermions remain controversial/missing. The resultant spectroscopic information is expected to lead to a deepened understanding of the interplay between strong correlations and topology. Younger generation of scientists including graduate and undergraduate students are actively involved in this project by undertaking key experimental activities and trained for acquiring professional skills such as written and verbal dissemination of their work. All personnel involved in this project participate in outreach activities to elevate general public’s literacy in STEM fields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：在这个项目中，凝聚态物理学中的两个重要课题使用探索电子性质的技术进行研究。首先，在超导状态下没有耗散的电力传输是一个基本的话题，通过研究一组广泛的超导体来明确确定超导的机制。其次，该项目的另一半重点是拓扑绝缘体，这是一类新型的量子物质，其表面具有受保护的导电状态。当相互作用很强时，这种新特性是如何出现的还不清楚。为了解决这个尚未解决的问题，该项目将隧道光谱应用于不同形式和静水压力下的多种候选材料。包括研究生和本科生在内的年轻一代科学家积极参与这一项目，开展关键的实验活动，并接受培训，以获得书面和口头传播其工作的专业技能。技术摘要：本项目涉及凝聚态物理学的两个前沿研究课题：1-1-5重费米子超导体族中的配对机制，以及关联拓扑材料中强关联与拓扑之间的相互作用。电子隧穿光谱被用来揭示它们的关键光谱特性，这些特性对于微观理解底层物理是必不可少的。尽管在重费米子超导体中存在自旋涨落的配对机制被广泛接受，但1-1-5家族重费米子的关键实验特征仍然存在争议/缺失。由此产生的光谱信息，预计将导致强相关性和拓扑结构之间的相互作用的加深理解。包括研究生和本科生在内的年轻一代科学家积极参与这一项目，开展关键的实验活动，并接受培训，以获得书面和口头传播其工作的专业技能。该项目的所有参与人员都参加了旨在提高公众在STEM领域的素养的外展活动。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估而被认为值得支持。

项目成果

Spectroscopic evidence for the direct involvement of local moments in the pairing process of the heavy-fermion superconductor CeCoIn5

局部矩直接参与重费米子超导体 CeCoIn5 配对过程的光谱证据

• DOI: 10.1103/physrevb.103.224515
• 发表时间: 2021
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Shrestha, K.;Zhang, S.;Greene, L. H.;Lai, Y.;Baumbach, R. E.;Sasmal, K.;Maple, M. B.;Park, W. K.
• 通讯作者: Park, W. K.

Topological nature of the Kondo insulator SmB6 and its sensitiveness to Sm vacancy

• DOI: 10.1103/physrevb.103.155125
• 发表时间: 2021-04
• 作者: W. Park;J. Sittler;L. Greene;W. Fuhrman;J. Chamorro;S. Koohpayeh;W. A. Phelan;T. McQueen

Self-oxidation-formed boron oxide as a tunnel barrier in SmB6 junctions

自氧化形成的氧化硼作为 SmB6 结中的隧道势垒

• DOI: 10.1016/j.jallcom.2021.159841
• 发表时间: 2021
• 期刊: Journal of Alloys and Compounds
• 影响因子: 6.2
• 作者: Sittler, J.A.;Park, W.K.
• 通讯作者: Park, W.K.