共轭梯度法研究超晶格 Ga As/Al_xGa_(1-x)As的电子结构(英文)

ab initio CALCULATION FOR THE ELECTRONIC STRUCTURE OF GaAs/Al_xGa_(1-x) As SUPERLATTICES: CONJUGATE GRADIENT APPROACH

改进了一种从头计算方法—共轭梯度方法 ,研究了超晶格 Ga As/ A lx Ga1 - x A s的电子结构 .根据超晶格的基本方程 ,在固定电子密度 n(z)下 ,求解了基本方程的本征值和本征函数 ,并由它们组成新的 n(z) ,重复此过程直到得自洽解 .另按超晶格基本方程的具体情况 ,对每个 kz独立地应用了共轭梯度方法 ,此可大大节省与 Gram-Schm it正交化有关的时间 .计算了超晶格的两个最低子能带之间的能量差和 F ermi能量 。

The electronic structure of GaAs/Al xGa 1-x As superlattices has been investigated by an ab initio calculation method—the conjugate gradient (CG) approach.In order to determine that,a conventional CG scheme is modified for our superlattices:First,apart from the former scheme,for the fixed electron density n(z),the eigenvalues and eigenfunctions are calculated,and then by using those,reconstruct the new n(z).Also,for every k z,we apply the CG schemes independently.The calculated energy difference between two minibands,and Fermi energy are in good agreement with the experimental data.