First-principles study of interstitial oxygen in potassium dihydrogen phosphate crystals
First-principles study of interstitial oxygen in potassium dihydrogen phosphate crystals
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DOI：
10.1103/physrevb.72.184105
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发表时间：
2005-11
影响因子：
3.7
通讯作者：
Kunpeng Wang;C. Fang;Jianxiu Zhang;C. Liu
中科院分区：
文献类型：
--
作者：
Kunpeng Wang;C. Fang;Jianxiu Zhang;C. Liu
使用第一原理方法研究了磷酸二氢钾 (KDP) 中间隙氧的电子结构和中性态和带电态的几何分布。通过中性 O 间隙，能隙从密度泛函理论 (DFT) 值 $5.9\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ 降低到约 $4.2\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$，对应于双光子吸收$364\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ $(3.4\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$ 校正 $1.3\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ 后，由于使用 DFT 低估了带隙。单个电子的添加将能隙降低至 $1.4\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$。两个电子的添加导致KDP中形成孤立的间隙${\mathrm{H}}_{2}\mathrm{O}$分子，并伴随着两个氢键链的断裂，因此能隙中不会出现缺陷态。该结果可用于解释最近报道的 KDP 在激光诱导击穿过程中的分解。
The electronic structure and geometric distribution of neutral and charged states of interstitial oxygen in potassium dihydrogen phosphate (KDP) are investigated using a first-principles method. The energy gap is lowered to about $4.2\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ from the density-functional theory (DFT) value of $5.9\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ by a neutral O interstitial, which corresponds to a two-photon absorption of $364\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ $(3.4\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$ after correction of $1.3\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ due to the underestimation of the band gap using the DFT. The addition of a single electron lowers the gap to $1.4\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. The addition of two electrons leads to the formation of an isolated interstitial ${\mathrm{H}}_{2}\mathrm{O}$ molecule in KDP accompanied by the breaking of two hydrogen-bonded chains, and thus no defect states appear in the energy gap. The results can be utilized to explain the recently reported decomposition of KDP during a laser-induced breakdown.