Density-functional-theory calculations for the silicon vacancy
Density-functional-theory calculations for the silicon vacancy
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DOI：
10.1103/physrevb.74.165116
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发表时间：
2006-10
影响因子：
3.7
通讯作者：
A. F. Wright
中科院分区：
文献类型：
--
作者：
A. F. Wright
用模守恒赝势密度泛函理论和平面波基计算了硅空位在、、0和电荷态的原子构型和形成能。用两种不同形式的交换和关联在简单立方超晶胞中进行了计算：局域密度近似(LDA)和广义梯度近似的Perdew，Burke，Ernzerhof公式。对所有电荷态进行了布里渊区采样的收敛测试，并通过将215、511和999原子超晶胞的形成能外推到无限大的超晶胞来消除由于周期性重复空位之间的静电相互作用而产生的影响。与实验结果一致，GGA在荷电状态下产生对称性构型，而LDA则产生对称性。还计算了电荷态之间的跃迁能。实验中观察到的施主状态的负行为在GGA结果中重现，但在LDA结果中没有重现。LDA和GGA都预测了受体状态的负面行为。
The atomic configurations and formation energies of a silicon vacancy in the,, 0,, andcharge states have been computed using density-functional theory with norm-conserving pseudopotentials and a plane wave basis. Calculations were performed in simple cubic supercells using two different forms of exchange and correlation: the local-density approximation (LDA) and the Perdew, Burke, Ernzerhof formulation of the generalized-gradient approximation (GGA). Convergence with respect to Brillouin zone sampling was tested for all charge states, and effects due to electrostatic interactions between the periodically repeated vacancies were removed by extrapolating the formation energies obtained in 215-, 511-, and 999-atom supercells to an infinite sized supercell. In agreement with experimental results, the GGA yielded a configuration withsymmetry in thecharge state, whereas the LDA yieldedsymmetry. Transition energies between the charge states were also computed. The experimentally observed negative-behavior of the donor states was reproduced in the GGA results, but not in the LDA results. Both the LDA and GGA predict negative-behavior for the acceptor states.