KDP和尿素晶体电子结构的第一性原理研究

基于第一性原理的平面波超软赝势法对KDP(KH₂PO₄)和尿素(CH₄N₂O)晶体的能带结构、电子态密度、电荷差分密度以及布局分析进行了计算讨论.结果表明:尿素晶体中的C1-O1、C1-N1、N1-H2和N1-H1键都具有共价键特性,带隙值为4.636 eV,价带顶主要由H-1s与N、O的2p态贡献,导带底主要是H-1s与C、N、O的2p态贡献;KDP晶体的H1-O1键具有离子性而P1-O1则具有共价性,带隙宽度为5.713 eV,价带顶主要由O-2p以及P-3p贡献,导带底主要由H-1s、P-3s和3p以及K-4s和3p态贡献.

First principles study on electronic structures of KDP and urea crystals

Based on the first principles plane wave ultrasoft pseudopotential method, the energy band structures, electronic densities of states, charge difference densities and layouts of KDP(KH2PO4) and urea(CH4N2O) crystals are calculated and discussed. The results show that for urea crystal, the C1-O1, C1-N1, N1-H2 and N1-H1 bonds have covalent bond characteristics and its band gap is 4.636 eV, the top of valence band is mainly contributed by H-1s, N-2p and O-2p states, and the conduction band bottom is mainly contributed by H-1s, C-2p, N-2p and O-2p states. For KDP crystal, the H1-O1 bond is ionic, while P1-O1 is covalent, the band gap is 5.713 eV, the top of valence band is mainly contributed by O-2p and P-3p, and the conduction band bottom is mainly contributed by H-1s, P-3s and 3p, K-4s and 3p states.