Sanders Kyana M, Gressel Danica G, Fredrickson Rie T, Fredrickson Daniel C
Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
Inorg Chem. 2024 Apr 15;63(15):6626-6637. doi: 10.1021/acs.inorgchem.3c04390. Epub 2024 Apr 2.
Complex intermetallic phases are often constructed from domains derived from simpler structures arranged into hierarchical assemblies. These modular arrangements offer intriguing prospects, such as the integration of the properties of distinct compounds into a single material or for the emergence of new properties from the interactions among different domains. In this article, we develop a strategy for the design of such complex structures, which we term the interface nucleus approach. Within this framework, the assembly of complex structures is facilitated by : geometrical motifs shared by two parent structures that serve as a region of overlap to nucleate or seed the formation of a combined structure. Our central hypothesis is that the formation of an interface between structures at these motifs creates opportunities for the relief of atomic packing stresses, as revealed by Density Functional Theory-Chemical Pressure (DFT-CP) analysis: when corresponding interatomic contacts in two structures exhibit complementarity─negative CP with positive CP or intense CP with mild CP─the intergrowth allows for a more balanced packing arrangement. To illustrate the application of the interface nucleus concept, we analyze three modular intermetallic structures, the σ-phase (FeCr), PuNi, and CaCuAl types. In each case, the assembly of the structure can be connected to complementary CP features in an interface nucleus shared by its parent structures, while the distribution of the interface nuclei in the parents serves to template the geometry of the overall framework. In this way, the interface nucleus approach points toward avenues for the design of modular intermetallics from the CP schemes of potential partner structures.
复杂金属间相通常由源自更简单结构的畴构建而成，这些结构排列成分层组装体。这些模块化排列提供了有趣的前景，例如将不同化合物的性质整合到单一材料中，或者通过不同畴之间的相互作用产生新的性质。在本文中，我们开发了一种设计此类复杂结构的策略，我们称之为界面核方法。在此框架内，复杂结构的组装通过以下方式得以促进：两个母体结构共有的几何基序，作为重叠区域以成核或引发组合结构的形成。我们的核心假设是，在这些基序处结构之间形成界面会为缓解原子堆积应力创造机会，正如密度泛函理论 - 化学压力（DFT - CP）分析所揭示的那样：当两个结构中相应的原子间接触表现出互补性时 ── 负化学压力与正化学压力互补，或强化学压力与弱化学压力互补 ── 共生生长允许形成更平衡的堆积排列。为了说明界面核概念的应用，我们分析了三种模块化金属间结构，即σ相（FeCr）、PuNi和CaCuAl型。在每种情况下，结构的组装都可以与母体结构共有的界面核中的互补化学压力特征相关联，而母体中界面核的分布则用于确定整体框架的几何形状。通过这种方式，界面核方法为从潜在伙伴结构的化学压力方案设计模块化金属间化合物指明了途径。
