Al的微观组态与LaNi_(3.75)Al_(1.25)的结构和弹性第一性原理研究

First-principles study on the microarrangement of Al and structure and elasticity of LaNi_(3.75)Al_(1.25)

在全电子水平上,采用广义梯度近似密度泛函理论和全势能线性缀加平面波方法并结合二维立方拟合方法,对LaNi3.75Al1.25合金的晶体结构与弹性性质进行了理论研究.计算结果给出合金的晶格常数a=b=0.5137nm,c=0.4018nm,Al原子在晶胞中的微观分布为同时占据部分3g和2c等价格位,弹性常数C11+C12=281.2,C13=82.3,C33=227.3,以及体弹性模量B=124.5、切变模量G=68.2GPa.还对态密度、能带结构和电荷密度进行了计算分析,并给出材料LaNi3.75Al1.25的电子线性比热系数23.45mJ/molK2.

The density functional theory on the level of generalized gradient approximation and full-potential linearized augmented plane wave, and the two-dimensional cubic fitting method have been used to calculate the geometrical and elastic property of LaNi3.75Al1.25 compound. The results indicate that the substitutional Al atoms in this compound are most likely to occupy part of the equivalent positions of 3g and 2c. The optimized lattice parameters a = b = 0.5137 nm, c = 0.4018 nm, the elastic constants C11 ＋ C12 = 281.2, C13 = 82.3, C33 = 227.3, the bulk modulus B = 124.5 and shear modulus G = 68.2 GPa have also been worked out. The density of state, band structure and charge density have been presented, and the electronic specific heat 23.45 mJ/molK^2 for LaNi3.75Al1.25 has been estimated.