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作 者:罗昊 成鹏飞[1] 党子妍 耿可佳 周敏[1] 苏耀恒 LUO Hao;CHENG Peng-fei;DANG Zi-yan;GENG Ke-jia;ZHOU min;SU Yao-heng(Xi’an Polytechnic University,Xi’an 710048,China)
机构地区:[1]西安工程大学,西安710048
出 处:《中国陶瓷》2024年第9期15-22,共8页China Ceramics
基 金:国家自然科学基金(51277138);陕西省自然科学基础研究计划项目(2021JM-442)。
摘 要:采用基于密度泛函理论(DFT)的第一性原理超软赝势平面波方法,通过调整氧原子的位置使TiO_(6)八面体扭转,对比了氧八面体扭转前后CaCu_(3)Ti_(4)O_(12)(CCTO)的成键状况、能带结构、原子态密度及光频介电函数等性能参数的变化,发现Ti-O-Ti键扭转方向的变化对各原子的电荷、键长和布居几乎没有影响,但扭转角度的改变发挥了关键性作用。随着Ti-O-Ti键夹角的增大,Cu的电荷量增加,Cu—O键键长增大,布居数减小,同时介电常数显著增大,表明Cu—O键刚性约束被打破后有助于CCTO光频介电常数的增加。研究揭示了TiO_(6)八面体的扭转对CCTO宏观介电性能的影响,为基于微结构调控优化CCTO的介电性能提供了新思路。This study employed the first-principles ultra-soft pseudopotential plane-wave method based on density functional theory(DFT)to twist TiO6 octahedron by adjusting the position of oxygen atoms.The bonding situation,band structure,atomic state density,and optical frequency dielectric function of CaCu_(3)Ti_(4)O_(12)(CCTO)before and after oxygen octahedron torsion were compared.It was found that the change in the direction of Ti—O—Ti bond rotation had almost no effect on the charges,bond lengths,or populations of each atom,but the change in torsional angle played a crucial role.With an increase in the Ti—O—Ti bond angle,the amount of charge of Cu,the length of the Cu—O bond,population decreased,and the dielectric constant significantly increased,indicating that the rigid constraint of the Cu—O bond contributed to the increase in the optical dielectric constant of CCTO.This study reveals the influence of TiO6 octahedron torsion on the macroscopic dielectric properties of CCTO,providing new insights for optimizing the dielectric properties of CCTO based on adjusting the microstructure.
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