J. A. Camargo-Martínez, R. Baquero
In the last approximately ten years, a number of codes using different approaches have been successful in solving the old problem of calculating the band gap of semiconductors with reasonable accuracy. The GW approximation (GWA), based on perturbation theory, some hybrid functional proposals, and the Wien2k code implemented with the modified Becke-Jonhson potential (mBJLDA) are compared in this work. In particular, we studied 27 semiconductors for which we found low temperature experimental data. We found that the GWA gives the most accurate predictions. The Wien2k (mBJLDA) code is slightly less precise, in general. The Hybrid functionals are less accurate, on the overall. The GWA is definitely the most precise existing method nowadays. In 88% of the semiconductors considered the error was less than 10%. Both, the GWA and the mBJLDA potential, reproduce the band gap of 15 of the 27 semiconductors considered with a 5% error or less. An extra factor to be taken into account is the computational cost. If one would seek for precision without taking this factor into account, the GWA is the method to use. If one would prefer to sacrifice a little the precision obtained against the savings in computational cost, the empirical mBJLDA potential seems the appropriate method. We include a graph that compares directly the performance of the best three methods, according to our analysis, for each of the 27 semiconductors studied. The situation is encouraging but the problem is not yet a closed issue.
View original:
http://arxiv.org/abs/1208.2057
No comments:
Post a Comment