GGA+U是近年来在第一原理计算领域中广泛使用的一种方法。它是从密度泛函理论(DFT)中发展而来的,旨在修正DFT在描述强关联体系时的局限性。本文将介绍GGA+U的原理及其在实际计算中的应用。 GGA+U方法的核心是将一种赝势(pseudo-potential)算法与LDA/GGA(局域密度近似/广义梯度近似)泛函相结合。其中,赝势算法是一种...
Based on first-principles calculation the change of magnetic configurations and electronic structure of perovskite oxide BaFeO3 is investigated by introducing a new potential energy function which has been determined via the density functional theory basis with U-Hubbard Hamiltonian (DFT+U). The exchang...
3、当然，DFT+U的U确实只是一种近似的修正方式，考察相对能量会比总能更有效一些。同时，无论是U本身...
Based on first-principles calculation the change of magnetic configurations and electronic structure of perovskite oxide BaFeO3 is investigated by introducing a new potential energy function which has been determined via the density functional theory basis with U-Hubbard Hamiltonian (DFT+U). The exchang...
构型优化做了DFT+U算声子频率显然要加，GGA+U的Hamiltonian和GGA是不一样的，这样两者的势能面也很可能...
scf.Hubbard.U on <Hubbard.U.values # eV Mn 1s 0.0 2s 0.0 3s 0.0 1p 0.0 2p 0.0 1d 4.0 P 1s 0.0 2s 0.0 1p 0.0 2p 0.0 1d 0.0 1f 0.0 Hubbard.U.values> scf.ElectronicTemperature 300.0 # default=300 (K) scf.energycutoff 200.0 # default=150 (Ry) ...
GGA+U calculation were performed for oxides of Ti, V, Mo, and Ce with the objective of establishing the best value of the parameter Ueff to use in order to match the calculated reduction and oxidation energies of each oxide with experimental values. In each case, the reaction involved the ...
Our ab initio calculations are based on the density functional theory (DFT) and have been conducted using the generalized gradient approximation (GGA, with PW91 & PBE versions) as well as GGA + U approach, in which an additional Hubbard- U term is added for the treatment of strong on-site...
采用基于第一性原理的计算软件VASP对Mg3Ce的基态结构分别在GGA方法和GGA+U方法下进行了研究.通过GGA计算得到的结构常数与实验值吻合,但是计算结果表明基态结构为铁磁结构,而且所得到的磁矩为0.94μB,这些都与实验值不符合.为了更好地描述Mg3Ce的性质,我们引入了GGA+U计算,结果表明当Ueff=7.0eV的时候所得到的结构...
1、是否设置初始磁矩？不设置开自旋极化默认全是1，如果体系也可能因为初猜初猜问题再加上DFT+U引起铁...