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：在该项目中，使用探索电子特性的技术来研究凝聚态物理中的两个重要主题，首先，超导状态下无耗散的电力传输是通过研究广泛的超导体来解决的一个基本主题。其次，该项目的另一半重点是拓扑绝缘体，这是一种表面具有受保护导电态的新型量子物质，这种新颖的特性是如何出现的。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该项目。计划开展关键实验活动并接受培训以获取专业技能，例如向代表性不足的群体进行书面和口头传播，以及参与旨在提高公众在 STEM 领域的素养的各种活动。技术摘要：该项目。涉及凝聚态物理的两个前沿研究课题：1-1-5族重费米子超导体中的配对机制以及相关拓扑材料中强相关性和拓扑之间的相互作用，利用电子隧道光谱来揭示其关键的光谱特性。尽管广泛接受的配对机制涉及重费米子超导体的自旋涨落，但 1-1-5 族的关键实验特征仍然至关重要。重费米子仍然存在争议/缺失，由此产生的光谱信息预计将加深对强相关性和拓扑之间相互作用的理解，包括研究生和本科生在内的年轻一代科学家通过开展关键实验活动和培训积极参与该项目。获得专业技能，例如书面和口头传播其工作成果。参与该项目的所有人员都参加外展活动，以提高公众在 STEM 领域的素养。该奖项反映了 NSF 的法定使命，并通过评估被认为值得支持。利用基金会的智力优势和更广泛的影响审查标准。

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.