Tuesday, June 19, 2012

1206.3780 (J. A. Camargo-Martinez et al.)

Detailed analysis of the performance of the modified Becke-Johnson
potential
   [PDF]

J. A. Camargo-Martinez, R. Baquero
Very recently, in the 2011 version of the Wien2K code, the long standing short come of the codes based on Density Functional Theory, namely, its impossibility to account for the experimental band gap value of semiconductors, was overcome. The novelty is the introduction of a new exchange and correlation potential, the modified Becke-Johnson potential (mBJLDA). In this letter, we report our detailed analysis of this recent work. We calculated using this code, the band structure of forty one semiconductors and found an important improvement in the overall agreement with experiment as Tran and Blaha [{\it Phys. Rev. Lett.} 102, 226401 (2009)] did before for a more reduced set of semiconductors. We found that by using the average of the two lattice parameters (LDA and GGA) a better agreement with the band gap experimental value is systematically obtained. On the other hand, the band structure calculated with the mBJLDA potential seems, at first sight, a simple rigid displacement of the conduction bands towards higher energies. We conclude that, in spite of the very important improvement in the band gap agreement with experiment using the new mBJLDA potential, there are issues that point to the fact that this problem is not yet totally closed.
View original: http://arxiv.org/abs/1206.3780

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