Comparative first-principles molecular dynamics study of TiN(001)/SiN/TiN(001) and TiN(001)/SiC/TiN(001) interfaces in superhard nanocomposites

摘要

Heterostructures TiN(001)/SiN/TiN(001) and TiN(001)/SiC/TiN(001), with oneudmonolayer (ML) of interfacial SiN and SiC, respectively, inserted between five monolayerudthick B1-TiN, were investigated using first-principles quantum molecular dynamicsud(QMD) calculations. The temperature dependent QMD simulations at 300 K inudcombination with subsequent variable-cell structural relaxation revealed that theudTiN(001)/SiN/TiN(001) interface exists as pseudomorphic B1-SiN layer only at 0 K,udand as a superposition of distorted octahedral SiN6 and tetrahedral SiN4 units alignedudalong the (110) direction at a finite temperature. Thus, at 300 K, the interfacial layer isudnot epitaxial. Instead it consists of aggregates of the B1-SiN-like and Si3N4-like distortedudclusters. However, in the the TiN(001)/SiC/TiN(001) heterostructures, the interfacialudlayer remains epitaxial B1-SiC at 0 K as well as at 300 K, with only a small shift ofudnitrogen atoms on both sides of the interface towards the silicon atoms. A comparisonudwith the results obtained by earlier "static" ab initio DFT calculations at 0 K shows theudgreat advantage of the QMD calculations that allow us to reveal structural reconstructionsudcaused by thermal activation.When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20546