铌酸锂晶体中的氢离子及其影响的第一性原理研究

First-Principles Study of Hydrogen Ions in Lithium Niobate Crystals and Their Influences on Optical Absorption

利用密度泛函理论,研究铌酸锂晶体(LN)和掺镁铌酸锂晶体中不可避免引入的氢离子的占位情况及对晶体吸收谱线的影响.研究结果认为H离子将占据锂位且微偏离该位置与附近的氧平面靠近,并与其中的氧原子结合形成OH结构.通过对LN,Mg∶LN,H∶Mg∶LN的建模和计算,发现各晶体的吸收谱线向不同方向偏移.该文提出了OH-和OH2-结构的形成该结构对吸收谱线产生影响的机制.

Using the density functional theory ,the authors study lithium niobate （LN） and Mg doped lithi‐um niobate crystals with inevitable introduction hydrogen ions .Through structural optimization ,the posi‐tion of the H ion is considered to occupy the lithium site ,offset from this position and unite with one oxy‐gen atom to form an OH structure .For LN ,Mg∶LN and H∶Mg∶LN samples ,they find that the ab‐sorption line edge of each crystal displaces in different directions ,and propose the formation of O H2 - and O H - structures and the mechanism of their influence upon absorption line .