Optimized effective potential using the Hylleraas variational method
Optimized effective potential using the Hylleraas variational method
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DOI：
10.1103/physrevb.85.235126
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发表时间：
2012-05
影响因子：
3.7
通讯作者：
T. Hollins;S. Clark;K. Refson;N. Gidopoulos
中科院分区：
文献类型：
--
作者：
T. Hollins;S. Clark;K. Refson;N. Gidopoulos
在电子结构计算中，优化有效势（OEP）是一种使用密度泛函理论（DFT）中的局部势精确处理交换相互作用的方法。我们提出了一种使用密度泛函微扰理论与 Hylleraas 变分方法相结合的方法，通过直接最小化来找到 OEP，避免了对未占用状态的任何求和。该方法已在平面波赝势形式中实现。使用 OEP 计算了闪锌矿半导体 Si、Ge C、GaAs、CdTe 和 ZnSe、纤锌矿半导体 InN、GaN 和 ZnO 以及岩盐绝缘体 CaO 和 NaCl 的能带结构，并与使用局域密度近似 (LDA)、广义梯度近似 (GGA) 和 Hartree-Fock (HF) 泛函的计算结果进行了比较。 OEP 发现的带隙改善了 LDA、GGA 或 HF 的计算结果，Si 的计算值为 1.16eV，GaN 的计算值为 3.32eV，ZnO 的计算值为 3.48eV。与LDA相比，半核d态的OEP能量也大大提高。
In electronic structure calculations the optimized effective potential (OEP) is a method that treats exchange interactions exactly using a local potential within density-functional theory (DFT). We present a method using density functional perturbation theory combined with the Hylleraas variational method for finding the OEP by direct minimization which avoids any sum over unoccupied states. The method has been implemented within the plane-wave, pseudopotential formalism. Band structures for zinc blende semiconductors Si, Ge C, GaAs, CdTe and ZnSe, wurtzite semiconductors InN, GaN and ZnO and the rocksalt insulators CaO and NaCl have been calculated using the OEP and compared to calculations using the local density approximation (LDA), a selection of generalized gradient approximations (GGAs) and Hartree-Fock (HF) functionals. The band gaps found with the OEP improve on the calculated results for the LDA, GGAs or HF, with calculated values of 1.16eV for Si, 3.32eV for GaN and 3.48eV for ZnO. The OEP energies of semi-core d-states are also greatly improved compared to LDA.