Adhesive and tensile properties of diamond(001)/TiC(111) interfaces: A first-principles investigation

Since a nanometer-thick carbide layer will be indispensably produced on diamond to ensure wettability with metallic parts, the interfacial properties of diamond/carbide directly affect the service performance of diamond devices. Herein, first-principles calculations were performed to investigate the interfacial properties and tensile responses of diamond(001)/TiC(111) interfaces. Taking into account Ti-and C-termination of TiC(111), and interfacial stacking of hollow-and top-site, four interface models were established. The results showed that Ti-termination could only be stacked by hollow-site. The analysis of energy and electronic structure suggested that hollow-site or C-termination favored to produce a more stable interface, attributing to stronger interfacial C-C covalent bonds and even the additional ionic attraction from Ti atoms, which enhanced the bonding strength significantly. Furthermore, the tensile simulations indicated cleavage always ignited from Ti-C bonds, of which along the interface for Ti-termination and within the TiC for C-termination. Growing C-terminated TiC could greatly improve interfacial stability, but at the expense of mechanical strength. This owed to the homogenization of C-termination by diamond surface. The results provided an atomic insight to characterize the structure and bonding of diamond/TiC interfaces, laying the foundation for developing high-performance diamond devices.

Automated summary

A nanometer-thick carbide layer is necessary on diamond to ensure compatibility with metal parts, and the properties of the diamond/carbide interface directly affect the performance of diamond devices. This study used first-principles calculations to investigate the properties and tensile responses of diamond(001)/TiC(111) interfaces. The results showed that hollow-site or C-termination favored a more stable interface due to stronger bonding and ionic attraction. Tensile simulations revealed that cleavage always started from Ti-C bonds. The findings provide atomic-level insight for characterizing diamond/TiC interfaces and lay the foundation for developing high-performance diamond devices.