Synthesis and Properties of Heterostructures Containing Magnetic 2d Layers Not Found As Bulk Compounds

含有未发现为本体化合物的磁性二维层的异质结构的合成和性能

• 批准号: 2219512
• 负责人: David Johnson
• 金额: $ 45万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2219512&HistoricalAwards=false
• 关键词: Synthesis; Properties; Heterostructures; Containing; Magnetic

NON-TECHNICAL SUMMARYThe 2010 Nobel prize in physics was awarded for the discovery of novel properties in monolayers of compounds with two dimensional (2D) structures that are not present in the bulk compounds. The resulting field of science - 2D materials and stacked layers of 2D materials known as heterostructures - has exponentially expanded as theorists proposed new exotic properties and experimentalists discovered new properties in monolayers and heterostructures. Currently the preparation of heterostructures is done by cleaving bulk materials to the monolayer limit and stacking them in designed sequences. This approach is limited to constituents that are stable as bulk compounds which are cleavable. New synthesis approaches are needed that enable preparation of heterostructures at a wafer scale, that provide a wider selection of constituent layers, and that provide control over the nanoarchitecture (stacking sequence and thickness of constituent layers). In this project, with the support of the Solid State and Materials Chemistry and Ceramics Programs in the Division of Materials Research, Dr. David Johnson and his research group at the University of Oregon, will develop new synthetic approaches to preparing heterostructures containing 2D magnetic constituent layers with structures and compositions that are not thermodynamically stable as isolated compounds. Three different strategies, all of which use precursors with targeted composition profiles that match that of the targeted heterostructures, are being tested. This research program provides a broad technical background for graduate students in deposition technologies, thin film characterization techniques, and physical phenomena that occur in 2D heterostructures. This training enables them to thrive in a variety of future careers (high tech industries, academia, or national laboratories). Internships will provide an opportunity for graduate students to “test drive” future careers while expanding their knowledge base, leading to more productive researchers. Engaging undergraduate students in this research enables them to apply principles learned in classes to solve research challenges. Providing undergraduate research opportunities is a critical tool to increase the number and diversity of students pursuing science as a career. TECHNICAL SUMMARYWith the support of the Solid State and Materials Chemistry and Ceramics Programs in the Division of Materials Research, Dr. David Johnson and his research group at the University of Oregon will develop synthetic approaches to preparing heterostructures containing 2D magnetic constituent layers with structures and compositions that are not thermodynamically stable as isolated compounds. Synthetic targets include diselenides (TSe2) and rock salt structured Pb2+nT1+mSe3+n+m layers, where T = Cr, Mn, Fe and Ni. Three synthesis strategies, which use precursors with targeted local composition and nanoarchitecture to control nucleation and growth, are being tested. One strategy is to prepare a precursor designed such that one layer crystalizes as 2D sheets separated by amorphous layers of controlled composition. The resulting 2D form factor and composition of the interleaved amorphous layers as well as the structure of adjacent crystalline layers will be used to control the nucleation and growth of the metastable constituent layers. A second strategy will be to seed nucleation of the desired structures by controlling local composition. A third strategy will be to use charge transfer from an adjacent layer to stabilize the targeted structures. The companion constituents in the targeted heterostructures will be critical to controlling the reaction pathways for each of these strategies, and our list of potential constituents include piezoelectric (GeSe, SnSe), topological insulating (Bi2Se3, Bi2Te3), semiconducting (PbSe, MoSe2, SnSe2) and/or superconducting (NbSe2) layers. A rich collection of new materials with diverse and tunable emergent properties is anticipated.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2010年诺贝尔物理学奖是因为发现了具有两个尺寸（2D）结构的化合物单层中的新型特性，这些物质是在散装化合物中不存在的。所产生的科学领域 - 2D材料和2D材料的堆叠层被称为异质结构 - 随着理论提出的新的外来特性，实验者发现了单层和异质结构中的新特性。目前，异质结构的制备是通过将散装材料切割到单层极限并将其堆叠在设计序列中来完成的。这种方法仅限于稳定的构造，这些结构是可裂解的散装化合物。需要采用新的综合方法，以便以晶圆规模制备异质结构，从而提供更广泛的构造层选择，并提供对纳米结构的控制（堆叠序列和建设性层的厚度）。在该项目中，在材料研究部的固态和材料化学和陶瓷计划的支持下，俄勒冈大学的David Johnson博士及其研究小组将开发新的合成方法，以准备含有2D磁性构造层的异质结构，这些层构造层具有与热力学稳定的隔离化合物的结构和成分。正在测试三种不同的策略，所有这些策略都使用具有靶向异质结构的靶向成分曲线的前体。该研究计划为在2D异质结构中发生的沉积技术，薄膜表征技术和身体现象提供了广泛的技术背景。这项培训使他们能够在各种未来的职业（高科技行业，学术界或国家实验室）中壮成长。实习将为研究生提供一个机会，可以在扩大知识库的同时“测试”未来的职业，从而为更多的产品研究人员提供机会。参与本研究的本科生使他们能够在课堂上应用学到的原则来解决研究挑战。提供本科研究机会是增加从事科学作为职业的学生的数量和多样性的关键工具。技术摘要在材料研究部中的固态和材料化学和陶瓷计划的支持，俄勒冈大学的David Johnson博士及其研究小组将开发合成方法，以准备含有2D磁性构建层的结构和组合物，并不是热力稳定的，它们不稳定为分离的化合物。合成靶标包括二苯甲酸酯（TSE2）和岩盐结构的PB2+NT1+MSE3+N+M层，其中T = Cr，Mn，Fe和Ni。正在测试三种综合策略，这些策略使用具有靶向局部组成和纳米结构的前体来控制成核和生长。一种策略是准备一个设计的前体，以使一个层晶体为2D纸，被无形组成的无定形层隔开。所得的2D形状和交织的无定形层的组成以及相邻晶体层的结构将用于控制稳定构造层的成核和生长。第二种策略将是通过控制局部组成来播种所需结构的核。第三个策略将是使用从相邻层的电荷转移来稳定目标结构。目标异质结构中的伴侣构造对于控制每​​种策略的反应途径至关重要，而我们的潜在列表构成了压电（GESE，SNSE），拓扑隔热（BI2SE3，BI2TE3），半导体，半导体（PBSE，MOSE2，SNSE2，SNSE2）和/或超级（NBSE2）。预计将有大量具有潜水员和可调的新兴材料的新材料。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来支持的。