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：在此项目中，使用探索电子特性的技术研究了凝结物理学的两个重要主题。首先，在超导状态下，无需耗散的电力运输是这里解决的一个基本话题，该主题通过研究了广泛的超导体来确定超导性的机理。其次，该项目的另一半集中于拓扑绝缘子，这是一类新型的量子物质，该量子在其表面具有受保护的导电状态。当相互作用很强时，尚不理解这种新颖的特性。为了解决这个未解决的问题，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。包括毕业生和本科生在内的年轻科学家通过开展关键的实验活动并获得了诸如书面和言语传播工作的专业技能，从而积极参与了该项目。计划与代表性不足的群体进行宣传，并参与各种活动，重点是提高公众在STEM领域的识字率。技术摘要：该项目涉及凝聚态物理学的两个前沿研究主题：1-1-5个重型超级负责人的1-1-5家族中的配对机制在强质超负管和强度的相互效果之间以及托架材料之间的相互效果。电子隧道光谱法被用于揭示其关键光谱特性，这对于对基础物理学的理解至关重要。尽管广泛接受的配对机制涉及重毛顶超导体中的自旋波动，但1-1-5个重型费米子家族的关键实验签名仍然有争议/缺失。预计所得的光谱信息将导致对强相关和拓扑之间的相互作用的深入了解。包括毕业生和本科生在内的年轻一代科学家通过开展关键的实验活动，并接受了培训的专业技能，例如书面和口头传播他们的工作，从而积极参与了该项目。参与该项目的所有人员都参加了外展活动，以提高公众在STEM领域的素养。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准通过评估来支持的。

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.