Exotic Quantum Liquid Phases Due to Intrinsic Degrees of Anisotropy

由于固有的各向异性程度而产生的奇异量子液相

基本信息

批准号：
2001980
负责人：
Orion Ciftja
金额：
$ 24万
依托单位：
Prairie View A & M University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-01-01 至 2024-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2001980&HistoricalAwards=false
关键词：
Exotic Quantum Liquid Phases Due

项目摘要

NONTECHNICAL SUMMARYThe Division of Materials Research and the Division of Human Resource Development contribute funds to this award. It supports fundamental theoretical and computational research and education involving the study of electrons confined to two dimensions and subject to interactions and crystal environments that lead to a preferred direction.Atoms and molecules are made of elementary particles such as electrons, protons, and neutrons. Electrons are often tightly bound to their atoms. Materials are made of many billions of atoms, and in metals and semiconductor materials some electrons can move relatively freely. These electrons can behave like a liquid and can easily respond to externally applied fields, such as electric fields, magnetic fields, and applied pressure. For example, a copper wire conducts electricity in response to an applied electric field.Since many interesting properties of materials are determined by the behavior of such free electrons, it is natural to study the nature of the possible states of electronic matter that arise in large systems of electrons and the dependence of their properties on external parameters, such as temperature, electron density, and applied magnetic field. The PI will study electronic states in materials where free electrons are restricted to two-dimensions where the interaction between electrons and quantum effects may combine leading to new phenomena and new electronic states of matter. The electrons may be in a uniform liquid state of matter if interactions are not very strong. The properties of such a liquid state would be isotropic - the same in all directions. However, it is possible that effective interactions between electrons are anisotropic or direction dependent. The presence of the crystalline lattice of atoms makes electrons behave as though they have an effective mass that can depend on the direction of their motion. This may lead to electrons behaving like a liquid of elongated rods leading to electronic states analogous to those assumed by the rod-like molecules in a liquid crystal display. The PI will investigate electronic states that may arise as a consequence of anisotropy. This includes externally induced anisotropy, such as the anisotropic states that could arise under the application of a strong magnetic field perpendicular to the 2D world of the electrons. The investigation of new electronic states adds to the intellectual foundations that lead to new electronic device technologies. The research activities conducted in this project will lead to research opportunities for economically challenged students in the setting of a HBCU, will enhance research and education in an undergraduate environment, and will improve the preparation of undergraduate students for graduate studies. Overall, this project will help to enhance the research and the education infrastructure at the local institution, and lead to broader participation of underrepresented groups in science.TECHNICAL SUMMARYThe Division of Materials Research and the Division of Human Resource Development contribute funds to this award. It supports fundamental theoretical and computational research to investigate the emergence of novel anisotropic exotic quantum liquid phases in strongly correlated Fermi systems. The PI will study two-dimensional systems of electrons in the quantum Hall regime and two-dimensional Fermi liquid phases with deformed Fermi surfaces in presence of some internal degree of anisotropy. The PI aims to understand how anisotropic electronic ordered states arise in various quantum phases in response to intrinsic anisotropy of the system. The PI will also investigate the nature of novel exotic anisotropic phases such as anisotropic quantum Hall liquid phases driven by an anisotropic interaction potential and anisotropic Fermi liquid phases with deformed Fermi surfaces driven by a combination of anisotropic effective mass and an anisotropic interaction potential between electrons.The theoretical approaches can be applied to experiments on two-dimensional electron systems with strong mass anisotropy where unusual anisotropic transport in the quantum Hall regime is anticipated. The ideas of this research can be relevant to understand experiments in two-dimensional systems of electrons confined in aluminum arsenide quantum wells and related systems. The electron effective mass anisotropy ratios can be almost one order of magnitude in these systems. Of particular interest is how tuning piezoelectric properties effects the anisotropic effective electron interactions, and the resulting experimentally observable consequences. Experiments may be proposed to detect signatures in transport properties resulting from the interplay of different sources of anisotropy. The PI will consider other physical systems as well, including ultracold atoms in anisotropic lattice traps. The PI and his team will use a combination of theoretical and computational methods, including exact diagonalization and quantum Monte Carlo, to carry out the research. Students will use methods suited to their skills, such as variational or perturbation methods from quantum theory, or computer simulations, in order to enhance their educational experience as appropriate. The research provides a setting for education and mentoring to enhance interest in science and leading careers in STEM. This project will help broaden participation of minority and economically challenged students in science and engineering through enhancing the pipeline.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.

非技术性摘要材料研究和人力资源开发部门为该奖项贡献了资金。它支持基本的理论和计算研究和教育，涉及局限于二维的电子研究，并受到导致优选方向的相互作用和晶体环境的影响。原子和分子由电子，质子和中子等基本颗粒制成。电子通常与原子紧密结合。材料由数十亿个原子制成，在金属和半导体材料中，某些电子可以相对自由移动。这些电子的表现可以像液体一样，并且可以轻松地响应外部施加的场，例如电场，磁场和施加的压力。例如，铜线响应于施加的电场而导致电力。由于材料的许多有趣的特性取决于这种自由电子的行为，因此自然可以研究电子物质的可能状态的性质，这些状态在大型电子系统中产生的电子物质及其属性依赖性在外部参数上的依赖性，例如温度，电子密度和磁场。 PI将研究电子状态在材料中的电子状态，在这些材料中，自由电子仅限于二维，在这些材料中，电子和量子效应之间的相互作用可能会结合导致新现象和物质的新电子状态。如果相互作用不是很强，则电子可能处于物质均匀的液态状态。这种液态的特性将是各向同性的 - 在所有方向上都是相同的。但是，电子之间的有效相互作用可能取决于各向异性或方向。原子的结晶晶格的存在使电子的行为好像它们具有有效的质量，可以取决于其运动方向。这可能会导致电子的行为就像伸长的杆的液体，导致电子状态类似于液晶显示器中杆状分子所假设的态。 PI将研究由于各向异性而可能出现的电子状态。这包括外部诱导的各向异性，例如在垂直于电子2D世界的强磁场下可能出现的各向异性状态。对新电子状态的调查增加了导致新电子设备技术的知识基础。该项目中开展的研究活动将为经济挑战的学生提供HBCU的研究机会，将在本科环境中增强研究和教育，并将改善本科生为研究生学习的准备。总体而言，该项目将有助于增强当地机构的研究和教育基础设施，并导致代表性不足的群体参与科学。技术摘要材料研究部和人力资源开发部门为该奖项贡献了资金。它支持基本的理论和计算研究，以研究在密切相关的费米系统中新型各向异性外来量子液相的出现。 PI将研究量子大厅制度中电子的二维系统和二维费米液相，在存在一些内部各向异性的情况下，具有变形的费米表面。 PI的目的是了解各向异性电子有序状态如何响应系统的内在各向异性而出现。 PI还将研究新型异国情感阶段的性质，例如由各向异性相互作用的潜力和各向异性费米液体相驱动的各向异性量子大厅液体相，其在各向异性质量和各向异性互动之间的组合驱动的Fermi表面驱动的福尔米表面驱动。二维电子系统具有较强的质量各向异性，预计在量子大厅方面存在异常的各向异性转运。这项研究的思想可能与了解在铝砷氧化铝量子孔和相关系统中的二维电子系统中实验有关。在这些系统中，电子有效质量各向异性比率几乎可以是一个数量级。特别令人感兴趣的是，调整压电性能如何影响各向异性有效电子相互作用，以及由此产生的实验可观察到的后果。可以提出实验来检测不同各向异性来源相互作用引起的传输特性的特征。 PI也将考虑其他物理系统，包括各向异性晶格陷阱中的超低原子。 PI和他的团队将使用理论和计算方法的结合，包括精确的对角线化和量子蒙特卡洛，进行研究。学生将使用适合其技能的方法，例如量子理论或计算机模拟的变分或扰动方法，以便在适当的情况下增强其教育经验。这项研究为教育和指导提供了一种设置，以增强对STEM的科学和领导职业的兴趣。该项目将通过加强管道来帮助扩大少数民族和经济挑战的科学和工程学生的参与。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的审查标准，被认为值得通过评估来获得支持。