CAREER: Engineering artificial oxide layers with hidden spin symmetry for drivable 2D quantum magnetism

职业：设计具有隐藏自旋对称性的人造氧化物层，以实现可驱动的二维量子磁性

• 批准号: 1848269
• 负责人: Jian Liu
• 金额: $ 70.83万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1848269&HistoricalAwards=false
• 关键词: CAREER; Engineering; artificial; oxide; layers

Nontechnical abstract: Magnetic materials have been known and exploited for applications since the ancient times of human history. While their advanced use in modern days can be commonly found in computers and electronics, new magnetic materials are necessary for developing a next generation of processors, memories, and sensors with better security, faster speed, and smaller size. Two-dimensional quantum antiferromagnet holds such promise because of its high scalability in the form of atomic layers. However, antiferromagnets, unlike ferromagnets, intrinsically resist control with a magnetic field. Moreover, realizing two-dimensional magnets is highly challenging because real materials are three dimensional. To overcome these difficulties, it is necessary to develop the capability of material synthesis by design with atomic precision. This research focuses on atomic layering of oxide materials to achieve quantum antiferromagnets that are not only two-dimensional but also externally controllable. Specifically, iridium-based oxides are used to realize a design where the antiferromagnet retains its internal magnetic structure and yet responds to magnetic field in a way similar to a ferromagnet. The project involves a revamp of undergraduate physics course materials, along with an outreach component that specifically targets underrepresented minorities and the general public.Technical abstract: Achieving control of two-dimensional quantum Heisenberg antiferromagnets is not only advancing our understanding of quantum many-body physics but also enables exploitation of quantum effects for new technologies. Realizing efficient external control is however highly challenging because of no direct linear coupling of an external magnetic field to the antiferromagnetic order. Moreover, internal spin anisotropy and three-dimensional coupling are always present in real materials, suppressing the two-dimensional critical fluctuations. While these barriers are difficult to overcome in bulk materials, the principle investigator plans to employ in-situ-monitored pulsed-laser deposition growth to construct a variety of atomically thin epitaxial oxide layers with strong spin-orbit coupling that creates large anisotropic exchange interactions and spin canting but preserves the spin rotational symmetry. The resulting two-dimensional quantum antiferromagnetic lattices is expected to be in close proximity to the spin isotropic limit and exhibits iant responses to applied external fields. This unique mechanism can be implemented by engineering the thicknesses, structural distortions, composition, and strain state of the oxide layers through epitaxial growth. An important goal is to unveil the two-dimensional critical fluctuations near quantum phase transitions, and to establish external controls of the antiferromagnetic order parameter via a suite of characterization techniques, including advanced synchrotron x-ray scattering and spectroscopy. The results are expected to facilitate the development of functional two-dimensional quantum antiferromagnets.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：磁性材料自人类历史的远古时代起就被人们所熟知并被开发应用。虽然它们在现代的先进应用通常可以在计算机和电子产品中找到，但新的磁性材料对于开发具有更好安全性，更快速度和更小尺寸的下一代处理器，存储器和传感器是必要的。二维量子反铁磁体具有这样的前景，因为它以原子层的形式具有很高的可扩展性。 然而，反铁磁体与铁磁体不同，本质上抵抗磁场的控制。此外，实现二维磁体是高度挑战性的，因为真实的材料是三维的。为了克服这些困难，有必要通过原子精度的设计来开发材料合成的能力。本研究的重点是氧化物材料的原子分层，以实现量子反铁磁体，不仅是二维的，而且是外部可控的。具体地说，铱基氧化物被用来实现一种设计，其中反铁磁体保持其内部磁性结构，但以类似于铁磁体的方式响应磁场。该项目涉及修改本科物理课程教材，沿着一个外展部分，专门针对代表性不足的少数群体和普通公众。技术摘要：实现二维量子海森堡反铁磁体的控制不仅可以推进我们对量子多体物理的理解，还可以利用量子效应开发新技术。然而，实现有效的外部控制是非常具有挑战性的，因为没有直接的线性耦合的外部磁场的反铁磁秩序。此外，在真实的材料中，内部自旋各向异性和三维耦合总是存在的，抑制了二维临界涨落。虽然这些障碍是很难克服的散装材料，主要研究人员计划采用原位监测脉冲激光沉积生长，以构建各种原子级薄的外延氧化物层与强大的自旋轨道耦合，创造大的各向异性交换相互作用和自旋倾斜，但保留自旋旋转对称性。由此产生的二维量子反铁磁晶格预计将接近自旋各向同性极限，并表现出对外加场的强烈响应。这种独特的机制可以通过外延生长来设计氧化物层的厚度、结构变形、成分和应变状态来实现。一个重要的目标是揭示量子相变附近的二维临界波动，并通过一套表征技术，包括先进的同步加速器X射线散射和光谱学，建立反铁磁序参数的外部控制。该奖项反映了NSF的法定使命，并被认为值得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来支持。

项目成果

Laser-induced transient magnons in Sr3Ir2O7 throughout the Brillouin zone

• DOI: 10.1073/pnas.2103696118
• 发表时间: 2020-02
• 期刊: Proceedings of the National Academy of Sciences
• 作者: D. Mazzone;D. Meyers;Yue Cao;J. G. Vale;C. D. Dashwood;Youguo Shi;A. James;N. Robinson;Jiaqi Lin;V. Thampy;Yoshikazu Tanaka;Allan S. Johnson;H. Miao;Ruitang Wang;Tadesse A. Assefa;Jungho Kim;D. Casa;R. Mankowsky;D. Zhu;R. Alonso-Mori;Sanghoon Song;H. Yavas;T. Katayama;M. Yabashi;Y. Kubota;S. Owada;Jian Liu;Junji Yang;R. Konik;I. Robinson;John P. Hill;D. McMorrow;M. Först;S. Wall;Xuerong Liu;M. Dean

Strongly anisotropic antiferromagnetic coupling in EuFe2As2 revealed by stress detwinning

• DOI: 10.1103/physrevb.104.104413
• 发表时间: 2020-12
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Joshua J. Sanchez;G. Fabbris;Yongseong Choi;Yue Shi;P. Malinowski;Shashi Pandey;Jian Liu;I. Mazin;Jong-Woo Kim;P. Ryan;J. Chu

Single-Laser-Pulse-Driven Thermal Limit of the Quasi-Two-Dimensional Magnetic Ordering in Sr2IrO4

• DOI: 10.1103/physrevx.11.041023
• 发表时间: 2021-10
• 期刊: Physical Review X
• 影响因子: 12.5
• 作者: Ruitang Wang;J. Sun;D. Meyers;J. Lin;J. Yang;G. Li;H. Ding;A. DiChiara;Y. Cao;J. Liu;M. Dean;H. Wen;X. Liu

Suppression of superconductivity by anisotropic strain near a nematic quantum critical point

• DOI: 10.1038/s41567-020-0983-9
• 发表时间: 2020-08-10
• 期刊: NATURE PHYSICS
• 影响因子: 19.6
• 作者: Malinowski, Paul;Jiang, Qianni;Chu, Jiun-Haw
• 通讯作者: Chu, Jiun-Haw

Epitaxial growth and antiferromagnetism of Sn-substituted perovskite iridate SrIr0.8Sn0.2O3

• DOI: 10.1103/physrevmaterials.3.124411
• 发表时间: 2019-12
• 期刊: arXiv: Materials Science
• 作者: Junyi Yang;L. Hao;Q. Cui;Jiaqi Lin;L. Horák;Xuerong Liu;Lu Zhang;Huaixin Yang;J. Karapetrova;Jong-Woo Kim;P. Ryan;M. Dean;Jinguang Cheng;Jian Liu