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

非技术摘要：在这个项目中，利用探索电子性质的技术研究了凝聚态物理中的两个重要课题。首先，超导状态下的无耗散输运是一个基本问题，本文通过研究一大批超导体来明确地确定超导的机制。其次，这个项目的另一半集中在拓扑绝缘体上，这是一种新型的量子物质，在其表面含有受保护的导电态。当相互作用很强时，这种新的性质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多种不同形式的候选材料，并在静水压力下进行。年轻一代的科学家，包括研究生和本科生，通过开展关键的实验活动积极参与这一项目，并接受培训，以获得书面和口头传播其工作等专业技能。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重费密子超导体的配对机制和相关拓扑材料中强关联和拓扑之间的相互作用。电子隧道光谱被用来揭示它们的关键光谱性质，这些性质对于微观理解潜在的物理是必不可少的。尽管重费米子超导体中涉及自旋涨落的配对机制被广泛接受，但1-1-5重费米子家族的关键实验特征仍然存在争议/缺失。由此产生的光谱信息有望加深对强关联和拓扑之间相互作用的理解。年轻一代的科学家，包括研究生和本科生，通过开展关键的实验活动积极参与这一项目，并接受培训，以获得书面和口头传播其工作等专业技能。参与该项目的所有人员都参与了提升普通公众在STEM领域的识字能力的外展活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.