KDP晶体中点缺陷Na取代K的电子结构研究
Electronic structure of defect of Na substituting for K in KH2PO4 crystals
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摘要: 对磷酸二氢钾(KDP)晶体中Na取代K点缺陷的几何结构及电子结构进行了第一性研究。计算的形成能约为0.46 eV，因此在KDP晶体中此类缺陷比较容易形成。Na取代K以后没有在带隙中形成缺陷态，但在价带中引入两个占据态。它们分别位于费米面以下49 eV和21.5 eV处，这两个占据态分别由Na原子的s和p轨道形成。相对于K来说，由于它们位于价带深处，具有很低的能量，因此Na在KDP中比K稳定。Na在KDP晶体中与周围氧原子的重叠布居仅为0.09, 故它不与主体原子发生共价作用，仅以静电库仑力影响周围原子，此缺陷周围晶格仅发生微小畸变。Abstract: The electronic structures of defect of Na substituting for K in KH2PO4 (KDP) crystals are studied by first-principles total-energy calculations based on density-functional theory. The calculated formation energy for this defect is about 0.46 eV. No defect states are induced in the energy gap, whereas two extra occupied states are induced in the valence band, which are located at -49 eV and -21.5 eV below the Fermi energy level, respectively.
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Key words:
- kdp crystals /
- point defects /
- formation energy /
- first-principle theory
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