Improving the modified Becke-Johnson exchange potential
نویسندگان
چکیده
The modified Becke-Johnson exchange potential [F. Tran and P. Blaha, Phys. Rev. Lett. 102, 226401 (2009)] (TB-mBJ) yields very accurate electronic band structures and gaps for various types of semiconductors and insulators (e.g., sp semiconductors, noble-gas solids, and transition-metal oxides). However, the TB-mBJ potential has, for a few groups of solids, the tendency to underestimate the band gap. This has led us to examine the possibility to further improve over the original TB-mBJ potential by either reparametrizing its coefficients using a larger test set of solids or defining a parametrization for small-/medium-size band-gap semiconductors only. We also checked alternatives to the average of |∇ρ|/ρ in the unit cell for the determination of parameter c, which determines the amount of the screening contribution. Among these different possibilities, the best one seems to be a reparametrization of the coefficients, which leads to a much more balanced description of the band gaps.
منابع مشابه
Merits and limits of the modified Becke - Johnson exchange potential
The modified Becke-Johnson exchange potential [F. Tran and P. Blaha, Phys. Rev. Lett. 102, 226401 (2009)] (TB-mBJ) is tested on various types of solids which are difficult to describe theoretically: nonmagnetic semiconducting transition-metal oxides and sulfides, metals (Fe, Co, Ni, and Cu), and (anti)ferromagnetic insulators (e.g., YBa2Cu3O6). The results for the band gap and other quantities ...
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