First-principles study of the Pd-Si system and Pd(001)/SiC(001) hetero-structure

Анотація

First-principles molecular dynamics simulations of the Pd(0 0 1)/3C–SiC(0 0 1) nano-layered structure were carried out at different temperatures ranging from 300 to 2100 K. Various PdSi (Pnma, Fmm, Pm2, Pmm), Pd₂Si (P2m, P6₃/mmc, Pm1, P1m) and Pd₃Si (Pnma, P₃22, Pmm, I4/mmm) structures under pressure were studied to identify the structure of the Pd/Si and Pd/C interfaces in the Pd/SiC systems at high temperatures. It was found that a large atomic mixing at the Pd/Si interface occurred at 1500–1800 K, whereas the Pd/C interface remained sharp even at the highest temperature of 2100 K. At the Pd/C interface, voids and a graphite-like clustering were detected. Palladium and silicon atoms interact at the Pd/Si interface to mostly form C22-Pd₂Si and D011-Pd₃Si fragments, in agreement with experiment.