Very recently, in the 2011 version of the Wien2K code, the long standing shortcome 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 paper, 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 [{\em Phys. Rev. Lett.} 102, 226401 (2009)] did before for a more reduced set of semiconductors. We find, nevertheless, within this enhanced set, that the deviation from the experimental gap value can reach even much more than 20%, in some cases. Furthermore, since there is no exchange and correlation energy term from which the mBJLDA potential can be deduced, a direct optimization procedure to get the lattice parameter in a consistent way is not possible as in the usual theory. These authors suggest that a LDA or a GGA optimization procedure is used previous to a band structure calculation and the resulting lattice parameter introduced into the 2011 code. This choice is important since small percentage differences in the lattice parameter can give rise to quite higher percentage deviations from experiment in the predicted band gap value.
Theoretical investigation of electronic, optical and thermoelectric properties of tellurium doped barium titanate (BTO) through modified Becke Johnson exchange potential
Assessing The Band Gap Problem By Improving Upon The Semilocal Exchange Hole Potential
一种类似于Becke-Schlosel [A. D. Becke和M. R.通过使用基于密度矩阵展开的广义坐标变换对交换孔进行建模来构造[Escherssel，Phys.Rev.A39，3761（1989）]。模型势是拉普拉斯自由的，系统中存在的不均匀性被包括在动量矢量中，而不影响均匀密度极限。与模型交换孔相关的参数与球形原子拟合。新构造的势函数与Tran-Blaha修正的Becke-Johnson势函数（TBMBJ）[F. Tran和P. Blaha，Phys. Rev. Lett. 102，226401（2009）]电势相当精确地产生从半导体到绝缘体的各种材料的带隙。与TBMBJ和其他标准半局域交换泛函相比，带隙的结果得到了改善。
Electronic structure and optical band gap determination of NiFe2O4
在理论研究中，我们调查的电子结构和带隙的反尖晶石型铁氧体NiFe 2 O 4。通过在修正的Becke-Johnson势中拟合Tran-Blaha参数，精确地再现了实验的光吸收谱。通常应用的Tauc图找到的光学间隙的准确性进行评估的基础上计算的光谱，我们发现，这种方法可能会导致误解的实验数据。NiFe_2 O_4的最小带隙为1.53eV宽的间接带隙，位于少数自旋通道中。
Prediction model of band-gap for AX binary compounds by combination of density functional theory calculations and machine learning techniques
利用Kohn-Sham带隙和其他组成元素和晶体结构的基本信息作为预测因子，应用机器学习技术建立了156 AX二元化合物G 0 W 0带隙的预测模型。普通最小二乘回归（OLSR），最小绝对收缩和选择算子（LASSO）和非线性支持向量回归（SVR）方法被应用于多个水平的预测集。当用GGA（PBE）或修正的Becke-Johnson（mBJ）的Kohn-Sham带隙作为单一预测因子时，OLSR模型预测了随机选取的测试数据的G 0 W 0带隙，均方根误差（RMSE）为0.54 eV。当通过PBE和mBJ方法的Kohn-Sham带隙与一组代表组成元素和晶体结构的各种形式的预测因子一起使用时，RMSE显著降低。SVR的最佳模型产生0.18 eV的RMSE。以这种方式估计的一组大的带隙应该是有用的材料探索的预测。
Efficient and improved prediction of the band offsets at semiconductor heterojunctions from meta-GGA density functionals
Accurate theoretical prediction of the band offsets at interfaces of semiconductor heterostructures can often be quite challenging. Although density functional theory has been reasonably successful to carry out such calculations and efficient and accurate semilocal functionals are desirable to reduce the computational cost. In general, the semilocal functionals based on the generalized gradient approximation (GGA) significantly underestimate the bulk band gaps. This, in turn, results in inaccurate estimates of the band offsets at the heterointerfaces. In this paper, we investigate the performa…
Computational study of structural, electronic and optical properties of crystalline NH$_4$N$_3$
采用基于密度泛函理论（DFT）的平面波赝势（PW-PP）方法，对正交晶系叠氮铵（NH $_4$ N $_3$）的结构、电子、成键和光学性质进行了系统的计算研究.半经验色散修正方案已被用来解释分子晶体NH $_4$ N $_3$中的非键相互作用。用色散修正方法得到的基态晶格参数和分数坐标与实验结果吻合得很好。我们计算了NH-$_4$-$_3$的单晶弹性常数，并通过观察到的弹性常数（C $_{33}$ $>$ C $_{11}$ $>$ C $_{22}$）的顺序解释了它的敏感性.采用全势线性缀加平面波（FP-LAPW）方法和最近开发的Tran-Blaha修正Becke-Johnson（TB-mBJ）势泛函计算了电子结构和光学性质。TB-mBJ电子结构表明NH $_4$ N $_3$是直接带隙绝缘体，带隙为5.08 eV，而用标准广义梯度近似计算的带隙为4.10 eV。通过计算三种不同晶轴方向的介电函数和折射率等光学常数，分析了晶体的光学各向异性。吸收光谱表明，NH $_4$ N $_3$对紫外光敏感。此外，我们还分析了NH $_4$ N $_3$的爆轰特性使用报告的生成热和计算的密度。用Kamlet-Jacobs经验公式计算得到NH $_4$ N $_3$的爆速为6.45 km/s，爆压为15.16 GPa。
Benchmarking exchange-correlation potentials with the mstar60 dataset: Importance of the nonlocal exchange potential for effective mass calculations in semiconductors
