Ir/SiC界面结合力、稳定性和电子结构的第一性原理研究

基于密度泛函理论（DFT）第一性原理研究了Ir(111)/SiC(111)界面。在考虑不同堆垛位置和表面封端的基础上，共研究了6种不同的界面构型。结果表明：具有9层原子层的Ir(111)表面构型表现体相材料的特征，而12层原子层的SiC(111)表面构型能体现体相SiC的性能。粘附功和界面能结果表明，C封端顶位堆垛（C-TS）和Si封端中心位堆垛（Si-CS）界面构型具有最大的粘附功，分别为6.35和6.23 J/m²，是最稳定的构型；弛豫后的界面能分别为0.07和0.10 J/m²。电子结构分析表明：C-TS界面处具有离子特性，而Si-CS界面处具有共价键特性。C-TS和Si-CS界面的结合强度和稳定性归因于Ir-d与C-p，Si-p轨道之间的杂化。与C-TS界面相比，Si-CS界面第2层原子与界面Ir原子的相互作用更大。

First-Principles Study on Adhesion, Stability, and Electronic Structure of Ir/SiC Interfaces

The Ir(111)/SiC(111) interfaces were investigated by first-principles study based on density functional theory (DFT). Considering different stacking sites and terminations, six different interfaces were studied. The results show that an Ir(111) slab with 9 atom layers exhibits bulk-like interior characteristic, while a 12-atom-layer SiC(111) slab represents the properties of bulk SiC. Adhesion and interfacial energy results show that the C-terminated top-site (C-TS) and Si-terminated center-site (Si-CS) interfaces are highly stable with the highest work of adhesion of 6.35 and 6.23 J/m², and the smallest interfacial energy of 0.07 and 0.10 J/m² after relaxation, respectively. Electronic structure analysis reveals that the C-TS interface has the ionic characteristics, while the Si-CS interface exhibits covalent bond characteristics. The bonding strength and stability of C-TS and Si-CS interfaces are attributed to the hybridization between Ir-d and C-p, Si-p orbits. Compared with the C-TS interface, sub-interfacial atoms have more interaction with Ir atoms in Si-CS interface.