NSF-BSF: Spectroscopy of excitonic insulators with direct gap

NSF-BSF：具有直接间隙的激子绝缘体的光谱学

• 批准号: 2105001
• 负责人: Girsh Blumberg
• 金额: $ 79.62万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2105001&HistoricalAwards=false
• 关键词: NSF; BSF; Spectroscopy; excitonic; insulators

Nontechnical Abstract:Interactions between particles making up a material can lead to surprising consequences, where the properties of the material as a whole are distinct from the properties of its constituents. The particles in question can be electrons, or electron holes, which are missing electrons in the material's atomic lattice. Interactions between electrons and holes in materials can lead to the emergence of such new properties – a frontier actively explored by condensed matter physics. An example of such interesting material is the excitonic insulator, with excitons being new particle-like entities in the material that appear due to the attractive interaction between electrons and holes. Such excitons are expected to achieve a novel quantum state, called "excitonic condensate" at sufficiently low temperatures. Theoretical predictions of its existence have never been fully confirmed by conclusive experimental evidence. This work aims at providing direct and convincing evidence for the excitonic condensate. This project also provides comprehensive training to postdocs and undergraduate students in low-temperature high-resolution spectroscopies, who will benefit from experiences brought by international collaborative efforts.Technical Abstract:The Rutgers-Technion NSF-BSF collaboration explores the conditions leading to the elusive state of excitonic insulator in solids by employing a combination of transport, angle-resolved photoemission (ARPES) and polarization-resolved light scattering (Raman) spectroscopies to concurrently study the properties and the dynamics of this state. The objective is to to derive the complete phase diagram for excitonic insulators that includes a structural instability intertwined with a semimetal-to-insulator transition and to establish plausible distinct regimes of the exciton condensation, identify the underlying microscopic mechanisms, and test the relevant theories. The lessons learned from this study will further promote broader understanding of self-organization in other strongly interacting quantum systems.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：构成材料的粒子之间的相互作用可能会导致令人惊讶的后果，其中材料整体的特性与其成分的特性不同。所讨论的粒子可以是电子，也可以是缺少电子的电子空穴。材料的原子晶格中的电子和空穴之间的相互作用可以导致这种新特性的出现——这是凝聚态物理学积极探索的前沿，这种有趣材料的一个例子是激子。绝缘体，激子是材料中由于电子和空穴之间的吸引相互作用而出现的新粒子状实体，预计在足够低的温度下会实现一种新的量子态，称为“激子凝聚”。这项工作旨在为激子凝聚体的存在提供直接和令人信服的证据，并为博士后和本科生提供低温方面的全面培训。高分辨率光谱学，他们将受益于国际合作努力带来的经验。技术摘要：罗格斯大学-以色列理工学院 NSF-BSF 合作通过结合输运、角分辨技术，探索导致固体中激子绝缘体难以捉摸的状态的条件光电发射（ARPES）和偏振分辨光散射（拉曼）光谱同时研究这种状态的性质和动力学。导出激子绝缘体的完整相图，其中包括与半金属到绝缘体转变交织在一起的结构不稳定性，并建立激子凝聚的合理的独特状态，确定潜在的微观机制，并测试相关理论。这项研究将进一步促进对其他强量子系统中相互作用的自组织的更广泛的理解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Crystal-field excitations and quadrupolar fluctuations of 4f-electron systems studied by polarized light scattering

通过偏振光散射研究 4f 电子系统的晶体场激发和四极涨落

• DOI: 10.1088/1742-6596/2164/1/012054
• 发表时间: 2022-03
• 期刊: Journal of Physics: Conference Series
• 作者: Ye, M;Kung, H H;Rosa, P F;Rosenberg, E;Kim, J;Xu, X H;Bauer, E D;Fisk, Z;Fisher, I R;Cheong, S W;et al
• 通讯作者: et al

Crystal-field excitations and vibronic modes in the triangular-lattice spin-liquid candidate TbInO3

三角晶格自旋液体候选 TbInO3 中的晶体场激发和电子振动模式

• DOI: 10.1103/physrevb.104.085102
• 发表时间: 2021-08
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Ye, Mai;Xu, Xianghan;Wang, Xiangyue;Kim, Jaewook;Cheong, Sang;Blumberg, Girsh
• 通讯作者: Blumberg, Girsh

Charge density wave order in the kagome metal AV3Sb5 (A=Cs,Rb,K)

Kagome 金属 AV3Sb5 中的电荷密度波阶 (A=Cs,Rb,K)

• DOI: 10.1103/physrevb.105.155106
• 发表时间: 2022-04
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Wu, Shangfei;Ortiz, Brenden R.;Tan, Hengxin;Wilson, Stephen D.;Yan, Binghai;Birol, Turan;Blumberg, Girsh
• 通讯作者: Blumberg, Girsh

Symmetry Breaking and Ascending in the Magnetic Kagome Metal FeGe

磁性 Kagome 金属 FeGe 的对称性破缺与提升

• DOI: 10.1103/physrevx.14.011043
• 发表时间: 2024-03
• 期刊: Physical Review X
• 影响因子: 12.5
• 作者: Wu, Shangfei;Klemm, Mason L.;Shah, Jay;Ritz, Ethan T.;Duan, Chunruo;Teng, Xiaokun;Gao, Bin;Ye, Feng;Matsuda, Masaaki;Li, Fankang;et al
• 通讯作者: et al

Failed excitonic quantum phase transition in Ta2Ni(Se1−xSx)5

Ta2Ni(Se1−xSx)5 中激子量子相变失败

• DOI: 10.1103/physrevb.104.l241103
• 发表时间: 2021-12
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Volkov, Pavel A.;Ye, Mai;Lohani, Himanshu;Feldman, Irena;Kanigel, Amit;Blumberg, Girsh
• 通讯作者: Blumberg, Girsh