Electronic structure and phase stability of GaAs1-xNx alloys.
Electronic structure and phase stability of GaAs1-xNx alloys.
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DOI：
10.1103/physrevb.51.10568
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发表时间：
1995-04
期刊：
影响因子：
--
通讯作者：
Neugebauer;Van de Walle CG
中科院分区：
文献类型：
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作者：
Neugebauer;Van de Walle CG
利用第一性原理总能量计算方法，研究了${\mathrm{GaAs}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{N}}_{\mathit{x}}$合金几种成分和各种有序结构的电子结构和稳定性。我们的结果显示了带隙的强烈弯曲，这与最近的实验观察是一致的。对于某些成分，合金甚至可能变成金属；这一过程主要是由强烈的原子弛豫驱动的。根据计算的生成能并假定热力学平衡，发现这两种结构之间存在很强的混溶间隙。这是由于GaAs和GaN之间的晶格常数失配很大(超过20%)。
Using first-principle total-energy calculations we investigated the electronic structure and stability for several compositions and for various ordered structures of ${\mathrm{GaAs}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{N}}_{\mathit{x}}$ alloys. Our results show a strong bowing of the band gap which is consistent with recent experimental observations. For certain compositions the alloy may even become metallic; a process which is mainly driven by a strong atomic relaxation. Based on the calculated formation energies and assuming thermodynamic equilibrium a strong miscibility gap between these two structures is found. This is explained in terms of the large mismatch in the lattice constants between GaAs and GaN (more than 20%).