Assessment of the GLLB-SC potential for solid-state properties and attempts for improvement

Abstract

Based on the work of Gritsenko et al. (GLLB) [Phys. Rev. A 51, 1944], the method of Kuisma et al. [Phys. Rev. B 82, 115106 (2010)] to calculate the band gap in solids was shown to be much more accurate than the common local density approximation (LDA) and generalized gradient approximation (GGA). The main feature of the GLLB-SC potential (SC stands for solid and correlation) is to lead to a nonzero derivative discontinuity that can be conveniently calculated and then added to the Kohn-Sham band gap for a comparison with the experimental band gap. In this work, a thorough comparison of GLLB-SC with other methods, e.g., the modified Becke-Johnson (mBJ) potential [F. Tran and P. Blaha, Phys. Rev. Lett. 102, 226401 (2009)], for electronic, magnetic, and density-related properties is presented. It is shown that for the band gap, GLLB-SC does not perform as well as mBJ for systems with a small band gap and strongly correlated systems, but is on average of similar accuracy as hybrid functionals. The results on itinerant metals indicate that GLLB-SC overestimates significantly the magnetic moment (much more than mBJ does), but leads to excellent results for the electric field gradient, for which mBJ is in general not recommended. In the aim of improving the results, variants of the GLLB-SC potential are also tested.

Efficient and accurate calculation of band gaps of halide perovskites with the Tran-Blaha modified Becke-Johnson potential

“…First and foremost, as discussed recently in ref. 36, the main problem of the TB-mBJ potential is basically to illegally provide band gaps in good agreement with experiment.…”

“…Among the affordable band gap correction schemes (see refs 35 and 36 for comparative studies), there is the Tran-Blaha modified Becke-Jonhnson (TB-mBJ) potential 37 , which has proven to be as accurate as hybrid functionals or GW for band gap prediction, but at a cost which is of the same order of magnitude as with LDA/GGA functionals. It has been quite successful for a variety of materials ranging from classical semiconductors, like Si or Ge, to strongly correlated transition-metal oxides (e.g., FeO or NiO) and rare-gas solids [35][36][37][38][39][40] .…”

“…where V cell is the unit cell volume, and α = −0.012 and β = 1.023 bohr 1/2 are the parameters that were determined from least square fitting of the experimental band gaps of a set of solids (see ref 37 for details). As discussed in refs 35,36,38 the TB-mBJ potential owes its success for band gaps to two of its ingredients, namely, t σ (which makes TB-mBJ a meta-GGA potential) and the average of |∇ρ| /ρ in the unit cell in Eq. (2).…”

DFT study of the electronic properties and the cubic to tetragonal phase transition in RbCaF3

“…Additionally, we also report calculations with the modified Becke-Johnson potential [42] (mBJ) for the electronic properties. The mBJ potential, which depends on the kinetic-energy density and is therefore of the meta-GGA class, is well known [43][44][45] to give significantly improved band gaps compared to standard GGA functionals like those considered in the present work.…”

Structural Stability and Magnetic Ordering in BiFeO3 Perovskite Oxide: A Comparative Study GGA+U vs L(S)DA+U

“…The spin effect between (FM) and (AFM) states can be described accurately by the Hubbard correction, while the pure (DFT) fails, because it doesn't give more description in the strong states due to the correlation in the d or f orbitals of the centered metal. Different approaches are employed in the present work to describe the exchange and correlation potential interaction, such as (Perdew-Wang) local spin density approximation (LSDA)[58] and corrected (LSDA+U)[59], the generalized gradient approximation (GGA)[60][61] and corrected (GGA+U)[62][63][64] in the structural properties calculation. The(GGA+U) as (LSDA+U) method are introduced to capture the strong correlation in d localized orbitals.…”