Acta Phys. -Chim. Sin. ›› 1998, Vol. 14 ›› Issue (03): 198-203.doi: 10.3866/PKU.WHXB19980302

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Calculations for Electronic Structure of TiC、TiC1-x and (Ti1-xNbx)C

Cui Wan-Qiu, Lei Ming   

  1. Department of Material Science,Wuhan University of Technology,Wuhan 430070
  • Received:1997-06-13 Revised:1997-09-10 Published:1998-03-15
  • Contact: Cui Wan-Qiu

Abstract:

Using the discrete-variational (DV-X_α) method, the electronic structures of TiC ideal crystal, carbon vacancies and Nb doped defect structure were investigated. We used the clusters to imitate the ideal crystal, C vacancies and Nb doped defect structure. The local density functional equation was self-consistently iterated by using SCM-DV-Xα method. The Fermi level lies between the two peaks in our results, where the DOS value is not equal to zero. This suggests the origin of the conductivity of TiC. For the vacancies cluster a peak was found near the Fermi level, thus the vacancy has the advantage of improving the conductivity of TiC. We also found a small peak near the Fermi level in the case of Nb doped cluster. Doping Nb also is beneficial to the conductivity. The influence of the boundaries of the clusters on the result was taken account of in the calculation. An environmental potential was used to eliminate the charge transition. On comparing our result with those of other authors, we found our results are well consistent with the experimental results.

Key words: DV-Xa method, Molecular cluster of TiC, Electronic structure