ATaO_3(A=K,Na)电子结构和光学性质的第一性原理研究

First-principles Calculation on Electronic Structure and Optical Properties of ATaO_3(A=K,Na)

采用第一性原理广义梯度近似(GGA)下的全电势线性缀加平面波(FP-LAPW)方法计算出立方相ATaO3(A=K,Na)的电子能带结构、态密度,发现了其光学性质.通过对两种材料的对比分析发现,KTaO3和NaTaO3价带顶均出现在0.15089eV处,KTaO3的导带底在2.02849eV处,NaTaO3的导带底在2.27339eV处,NaTaO3比KTaO3的导带底高,因而禁带宽度较大;NaTaO3中Ta5d电子和O2p电子之间的轨道杂化比KTaO3中的轨道杂化弱,Na的粒子性较K更强,因此,NaTaO3的光催化活性明显大于KTaO3.

In this paper the full potential linearized augmented plane wave（FP-LAPW）method with the generalized gradient approximation was performed to investigate the energy band structures,density of states（DOS）and optical properties of cubic ATaO3（A=K,Na）.The differences between KTaO3 and NaTaO3 were discussed.The results showed that the tops of the valence band（VB）for KTaO3 and NaTaO3 were both at 0.150 89 eV,but the bottom of the conduction band（CB）for KTaO3 was at 2.028 49 eV and that for NaTaO3 was at 2.273 39 eV.Consequently,the bottom of conduction band for NaTaO3 was higher than that for KTaO3 and NaTaO3 showed larger energy gap.There were weaker hybridizations of Ta 5d-O 2p bands for NaTaO3 than that for KTaO3,which reflected the stronger corpuscular property of Na.These played very important roles in the optical responses and photocatalytic activity of them and NaTaO3 shows much higher photocatalytic activity.