First-principles GW calculations of GaAs clusters and crystal using an all-electron mixed basis approach
First-principles GW calculations of GaAs clusters and crystal using an all-electron mixed basis approach
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DOI：
10.1103/physrevb.76.075325
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发表时间：
2007-08
影响因子：
3.7
通讯作者：
E. Kikuchi;S. Iwata;S. Ishii;K. Ohno
中科院分区：
文献类型：
--
作者：
E. Kikuchi;S. Iwata;S. Ishii;K. Ohno
从密度泛函理论的局域密度近似出发，采用全电子混合基方法，以平面波和原子轨道为基组，对砷化镓小团簇和砷化镓晶体进行了全电子GW计算.这种方法的优点是用较少的基函数就能精确地表示核电子态和类空自由电子态。目前的全电子GW方法使我们能够毫不费力地处理团簇和晶体。首先，我们确定了砷化镓团簇的最稳定结构，${\marthm {Ga}}_{n}{\marthm {As}}_{n}$，$n=2--4 $。对于这些团簇，由于在电离过程中的结构变化不是那么大相比，硅或锗团簇，有没有在垂直和绝热电子亲合势的显着差异。对于团簇和晶体，我们的一杆GW$准粒子能谱的结果同意相当不错，与现有的实验光电发射和逆光电发射数据。本文结果考虑了半相对论效应。
All-electron $GW$ calculations beginning with the local density approximation of the density functional theory are carried out for both small gallium arsenide clusters and gallium arsenide crystal in a consistent way by means of the all-electron mixed basis approach, in which both plane waves and atomic orbitals are used as a basis set. This approach has the merit of expressing both core electron states and empty free-electron-like states accurately with a rather small number of basis functions. The present all-electron $GW$ method enables us to treat both clusters and crystal without difficulty. First, we determined the most stable structures of gallium arsenide clusters, ${\mathrm{Ga}}_{n}{\mathrm{As}}_{n}$ with $n=2--4$. For these clusters, since the structural change in the ionization process is not so large compared to silicon or germanium clusters, there is no significant difference in the vertical and adiabatic electron affinities. For both clusters and crystal, our one-shot $GW$ results for quasiparticle energy spectra agree fairly well with available experimental photoemission and inverse photoemission data. The present results include the semirelativistic effect.