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Intrinsic defects, Mo‐related defects, and complexes in transition‐metal carbide VC: A first‐principles study
Author(s) -
Guo Jing,
Feng Yunli,
Tang Cong,
Ren Xuejun
Publication year - 2020
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17411
Subject(s) - vacancy defect , crystallography , carbide , atom (system on chip) , materials science , crystallographic defect , vanadium , molybdenum , vanadium carbide , lattice (music) , frenkel defect , transition metal , metal , interstitial defect , chemistry , physics , metallurgy , biochemistry , optoelectronics , doping , computer science , acoustics , embedded system , catalysis
Intrinsic defects and Mo‐related defects in vanadium carbide VC, as well as the defect complexes between vacancies and Mo defects were investigated by means of first‐principles calculations within the framework of density functional theory. In addition, Mo diffusion in VC was also studied using LST/QST method. The formation energies of defects have clearly shown that except C vacancy (V C ) all other point defects are not energetic favorable compared to perfect VC. V C can exist in the lattice forming nonstoichiometric carbide VC x (x < 1), and also can stabilize the Mo‐related defects (S Mo‐V , S Mo‐C , and T Mo ). Free Mo atoms have the strong tendency to enter the already formed V V and occupy the lattice position of V atoms. Meanwhile, Mo atom in C lattice (S Mo‐C ) and interstitial Mo (I Mo ) atom can also enter the V V position stabilizing the lattice structure. S Mo‐C + V V will transform into S Mo‐V + V C and I Mo + V V will transform into S Mo‐V during optimization, and large binding energy makes Mo atom tend to exist in the interstitial position. From the perspective of energy, Mo atom tends to diffuse through the interstitial position.