Impact of dopants and strains on the oxygen vacancy formation in VO2

초록

We perform first-principles calculations to examine the relationship of the oxygen vacancy (VO) formation with dopants and mechanical strains in metallic tetragonal VO2. Both compressive and tensile biaxial strains lower the formation energy of VO, and the lowering of the formation energy is more pronounced under tensile strain. When six dopants, which possess different charge state and ionic radius, are introduced, the formation energy of VO increases, indicating that the dopants may suppress the VO formation in VO2. Strains lead to similar trends in the undoped case, i.e., strains reduce the VO formation energy in the doped VO2. Based on the results, we suggest that the difference in atomic relaxations of the two kinds of V-O bonds plays an important role in determining the formation energy of VO.

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