Unconventional metals in carrier-tuned spin-orbit Mott materials

载流子调谐自旋轨道莫特材料中的非常规金属

• 批准号: 1905801
• 负责人: Stephen Wilson
• 金额: $ 50.18万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905801&HistoricalAwards=false
• 关键词: Unconventional; metals; carrier; tuned; spin

Nontechnical Abstract: This project explores the fascinating and complex electronic behaviors endemic to a class of metals born from insulators with both strong interactions between electrons and strong coupling between the electron's orbital motion and its inherent magnetic moment or spin. These 'spin-orbit assisted Mott insulators' can be turned into metals by adding charge carriers, where many exciting states such as high temperature superconductivity and electronic states for quantum information are predicted. Ultrahigh purity crystals of these metals are grown in the project and experiments exploring the structural, magnetic, and electronic properties of their unusual metallic states performed. In particular, research activities target a series of doped iridium oxide materials whose parent insulating states have recently been shown to collapse into metals with anomalous charge and spin properties. This builds the knowledgebase needed for assessing the viability of these materials for potential future superconducting and quantum information applications. The project trains graduate students in advanced crystal growth techniques as well as in advanced scattering techniques at national user facilities, addressing the national need for trained personnel in both arenas. Additionally, the project executes a multitier education and outreach effort targeted at promoting diverse participation in STEM disciplines and within materials science in particular. This is achieved through undergraduate research opportunities targeted at attracting and retaining underrepresented demographics within materials science.Technical Abstract: This project experimentally explores two classes of iridium oxides where canonical spin-orbit Mott states appear--the Ruddlesden-Popper series of Srn+1IrnO3n+1 and the rare-earth series of pyrochlore Al2Ir2O7. Key variants of these compounds are explored with the goals of understanding the origins of unconventional spin and charge density wave formation in the Ruddlesden-Popper iridates, their relation to strange-metal behavior and potential superconductivity in these systems, and the coupling between magnetism and the metal-insulator transitions of the pyrochlore iridates. All of these phenomena are of considerable interest for identifying exotic electronic states predicted to manifest in these materials, with examples ranging from high-temperature superconductivity to magnetic Weyl semimetal states. Experimental approaches include synchrotron x-ray and neutron scattering measurements, bulk electronic properties (such as charge transport and magnetization) measurements, and complementary electronic probes performed via a network of collaborators. A key enabling tool in the research is the use high-pressure floating zone crystal growth techniques to create ultrahigh purity specimens for study. By leveraging this tool, the project creates new pathways for discovering predicted and other unforeseen unconventional electronic states in carrier-doped spin-orbit assisted Mott materials.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：该项目探讨了一类由绝缘体产生的金属所特有的令人着迷且复杂的电子行为，这些金属具有电子之间的强相互作用以及电子轨道运动与其固有磁矩或自旋之间的强耦合。 这些“自旋轨道辅助莫特绝缘体”可以通过添加电荷载流子转变成金属，其中可以预测许多令人兴奋的状态，例如高温超导和量子信息的电子状态。 这些金属的超高纯度晶体是在该项目和实验中生长的，探索其不寻常金属态的结构、磁性和电子特性。 特别是，研究活动针对一系列掺杂氧化铱材料，其母体绝缘态最近已被证明会塌陷成具有异常电荷和自旋特性的金属。这构建了评估这些材料在未来潜在的超导和量子信息应用中的可行性所需的知识库。该项目在国家用户设施中对研究生进行先进晶体生长技术和先进散射技术的培训，满足国家对这两个领域训练有素的人员的需求。 此外，该项目还开展多层次的教育和推广工作，旨在促进 STEM 学科，特别是材料科学领域的多元化参与。 这是通过旨在吸引和保留材料科学领域代表性不足的人口统计数据的本科生研究机会来实现的。技术摘要：该项目通过实验探索了出现规范自旋轨道莫特态的两类氧化铱——Srn+1IrnO3n+ 的 Ruddlesden-Popper 系列1和稀土系列烧绿石Al2Ir2O7。 探索这些化合物的关键变体，目的是了解拉德尔斯登-波普尔虹彩中非常规自旋和电荷密度波形成的起源、它们与这些系统中的奇异金属行为和潜在超导性的关系，以及磁性和磁性之间的耦合。烧绿石铱酸盐的金属-绝缘体转变。 所有这些现象对于识别预计在这些材料中出现的奇异电子态都具有相当大的意义，示例范围从高温超导到磁性外尔半金属态。 实验方法包括同步加速器 X 射线和中子散射测量、体电子特性（例如电荷传输和磁化）测量以及通过合作者网络执行的互补电子探针。 研究中的一个关键工具是使用高压浮区晶体生长技术来创建用于研究的超高纯度样本。 通过利用该工具，该项目为发现载流子掺杂自旋轨道辅助莫特材料中的预测和其他不可预见的非常规电子态创造了新的途径。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进行评估，被认为值得支持以及更广泛的影响审查标准。

项目成果

Monopole-limited nucleation of magnetism in Eu2Ir2O7

Eu2Ir2O7 中磁性的单极限制成核

• DOI: 10.1103/physrevb.101.174435
• 发表时间: 2020-05
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Prando, Giacomo;Telang, Prachi;Wilson, Stephen D.;Graf, Michael J.;Singh, Surjeet
• 通讯作者: Singh, Surjeet

Electronic nature of the pseudogap in electron-doped Sr2IrO4

电子掺杂 Sr2IrO4 中赝能隙的电子性质

• DOI: 10.1038/s41535-022-00467-1
• 发表时间: 2022-12
• 期刊: npj Quantum Materials
• 影响因子: 5.7
• 作者: Peng, Shuting;Lane, Christopher;Hu, Yong;Guo, Mingyao;Chen, Xiang;Sun, Zeliang;Hashimoto, Makoto;Lu, Donghui;Shen, Zhi;Wu, Tao;et al
• 通讯作者: et al

Nonsymmorphic Dirac semimetal and carrier dynamics in the doped spin-orbit-coupled Mott insulator Sr2IrO4

掺杂自旋轨道耦合莫特绝缘体 Sr2IrO4 中的非对称狄拉克半金属和载流子动力学

• DOI: 10.1103/physrevb.102.041108
• 发表时间: 2020-07
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Han, J. W.;Kim, Sun;Kyung, W. S.;Kim, C.;Cao, G.;Chen, X.;Wilson, S. D.;Cheon, Sangmo;Lee, J. S.
• 通讯作者: Lee, J. S.

Incommensurate magnetic order in the Z2 kagome metal GdV6Sn6

Z2 kagome 金属 GdV6Sn6 中的不相称磁序

• DOI: 10.1103/physrevb.108.035134
• 发表时间: 2023-07
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Porter, Zach;Pokharel, Ganesh;Kim, Jong;Ryan, Phillip J.;Wilson, Stephen D.
• 通讯作者: Wilson, Stephen D.

Symmetry-Resolved Two-Magnon Excitations in a Strong Spin-Orbit-Coupled Bilayer Antiferromagnet

强自旋轨道耦合双层反铁磁体中对称分辨的双磁振子激发

• DOI: 10.1103/physrevlett.125.087202
• 发表时间: 2020-08
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Li, Siwen;Drueke, Elizabeth;Porter, Zach;Jin, Wencan;Lu, Zhengguang;Smirnov, Dmitry;Merlin, Roberto;Wilson, Stephen D.;Sun, Kai;Zhao, Liuyan
• 通讯作者: Zhao, Liuyan