发表机构
Tel Aviv University; Xi’an Jiaotong University; Inner Mongolia University of Science and Technology; China Academy of Engineering Physics（特拉维夫大学; 西安交通大学; 内蒙古科技大学; 中国工程物理研究院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究结合密度泛函理论与原子级基础模型，揭示了金刚石/cBN异质结构中界面化学、取向和相互混合如何控制断裂面选择，并建立了调控断裂抗力的原子级框架。
AI 中文摘要
一个初始无裂纹的异质结构是在其界面处失效还是在相邻相内失效，取决于竞争原子平面的相对内聚强度，但界面化学、晶体学取向和相互混合如何重塑这种竞争关系仍不清楚。在此，我们将密度泛函理论（DFT）与一个精细调优的原子级基础模型相结合，以解析共格金刚石/立方氮化硼（cBN）异质结构中的拉伸断裂。所得势函数重现了独立的DFT拉伸响应，包括一个未见过的（001）界面取向。界面终止、取向和扩散诱导的相互混合共同决定了断裂抗力和断裂面选择。C-N键合的（111）和C-B键合的（001）在所研究的相互混合范围内始终保持界面控制，而原始的C-B键合（111）在cBN内部相邻的B-N平面处断裂，因为界面结合更强。将扩散分数从0增加到50.0%会导致断裂强度从50.3 GPa非线性下降至15.8 GPa，并通过三个区域驱动体相到界面的转变：cBN断裂直至4.86%，7.6%至10.1%之间的构型依赖竞争，以及12.5%及以上的界面断裂。原子分辨应力场和DFT分离能量学表明，这种转变与应力重新分布和竞争平面相对内聚强度的反转有关，而电子局域化分析将内聚层级与终止和取向依赖的键合联系起来。这些结果为控制强键合异质结构中的断裂抗力和断裂路径建立了一个原子级框架。
英文摘要
Whether an initially crack-free heterostructure fails at its interface or within an adjoining phase is controlled by the relative cohesion of competing atomic planes, but how interfacial chemistry, crystallographic orientation, and intermixing reshape this competition remains unclear. Here, we combine density functional theory (DFT) with a fine-tuned atomistic foundation model to resolve tensile fracture in coherent diamond/cubic boron nitride (cBN) heterostructures. The resulting potential reproduces independent DFT tensile responses, including an unseen (001) interface orientation. Interfacial termination, orientation, and diffusion-induced intermixing jointly determine fracture resistance and fracture-plane selection. C-N-bonded (111) and C-B-bonded (001) remain interface-controlled throughout the investigated intermixing range, whereas pristine C-B-bonded (111) fractures at a neighboring B-N plane inside cBN because the interface is more strongly bound. Increasing the diffusion fraction from 0 to 50.0% causes a nonlinear decrease in fracture strength from 50.3 to 15.8 GPa and drives a bulk-to-interface transition through three regimes: cBN fracture up to 4.86%, configuration-dependent competition between 7.6 and 10.1%, and interfacial fracture at 12.5% and above. Atom-resolved stress fields and DFT separation energetics show that this transition is associated with stress relocation and a reversal in the relative cohesion of competing planes, while electron localization analysis connects the cohesion hierarchy to termination- and orientation-dependent bonding. These results establish an atomistic framework for controlling fracture resistance and fracture pathways in strongly bonded heterostructures.
Comments16 pages, 10 figures
