Confronting Complexity in Intermetallics: A Synthetic, Structural and Theoretical Approach

面对金属间化合物的复杂性：一种合成、结构和理论方法

• 批准号: 0504703
• 负责人: Stephen Lee
• 金额: $ 33万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0504703&HistoricalAwards=false
• 关键词: Confronting; Complexity; Intermetallics; Synthetic; Structural

TECHNICAL EXPLANATION This project addresses the synthesis, structural characterization, properties, and band calculations for, are phases in which there are lattice mismatches between two metal structural motifs (noble metal gamma-brass superstructures), large cubic phases which can be decomposed into simpler components, phases composed of concentric icosahedral symmetry clusters, and structures composed of extended electron deficient clusters. All these systems lay near the metal-insulator boundary, some on one side, some on the other, have complex scaling properties, and potentially contain interfaces between their more metallic (covalent) and more ionic components. They test the boundaries of current paradigms useful for pure metals, insulators or semiconductors. Students working on this project will learn how to apply modern electronic structure calculations to understand the complex crystal structures that can now be obtained through modern synchrotron radiation diffraction experiments.NON-TECHNICAL EXPLANATIONThe classic alloys of civilization, brass and bronze, the elements, copper silver and gold lie at the heart of the proposed project. Our understanding today of their structures is remarkably still often imbedded in classical notions: the Platonic polyhedra for example. This project aims at a coherent structural reworking of these structures and the other structures derived from them. It will be a reworking from a classical geometrical picture (still used in understanding structures of gamma-brass for example), to paradigms based on simple quantum mechanical calculations. It is anticipated that the understanding will evolve into models based on minimal surfaces and interlocking intermeshed substructures. The materials being studied are chosen not just because they have hitherto proven difficult to understand but also because we think that such materials possess an unusual balance of bonding trends that could very well lead to materials with novel properties such as segregation between ionic and metallic components , and sub-lattice shear patterns, properties which affect the electrical and magnetic and cohesion properties of these essential alloys.

TECHNICAL EXPLANATION This project addresses the synthesis, structural characterization, properties, and band calculations for, are phases in which there are lattice mismatches between two metal structural motifs (noble metal gamma-brass superstructures), large cubic phases which can be decomposed into simpler components, phases composed of concentric icosahedral symmetry clusters, and structures composed of extended electron deficient clusters.所有这些系统都位于金属 - 绝缘子边界附近，一侧有些，有些在另一侧具有复杂的缩放特性，并且可能包含其更高金属（共价）和更多离子成分之间的接口。他们测试对纯金属，绝缘体或半导体有用的当前范式的边界。从事该项目的学生将学习如何应用现代电子结构计算，以了解现在可以通过现代同步加速器辐射衍射实验获得的复杂晶体结构。没有技术解释，文明的经典合金，黄铜和青铜，元素，元素，铜银色和金色的核心位于提议项目的核心。 我们今天对它们的结构的理解仍然非常常见于古典概念中：例如，柏拉图式多面体。该项目的目的是对这些结构的连贯结构重新设计以及从它们衍生的其他结构。 这将是从经典的几何图片（例如，在理解γ-布拉斯的结构中使用）的重制，以基于简单的量子机械计算的范例。可以预料，理解将发展为基于最小表面和互锁的子结构的模型。选择所研究的材料不仅是因为它们迄今被证明难以理解，还因为我们认为这种材料具有粘结趋势的异常平衡，这很可能会导致具有新型属性的材料，例如离子和金属组件和金属组件之间的隔离，以及子层状剪切模式，以及影响电气和磁性和磁性特性的特性。