First-principles studies on structural and electronic properties of TaCr2 Laves phase
First-principles studies on structural and electronic properties of TaCr2 Laves phase
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DOI：
10.1016/j.physb.2010.07.025
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发表时间：
2010-10
影响因子：
2.8
通讯作者：
X. Nie;Yong Du;Hong-hui Xu
中科院分区：
文献类型：
--
作者：
X. Nie;Yong Du;Hong-hui Xu
用第一性原理计算方法研究了TaCr{sub 2}的结构性质、弹性性质和电子结构。计算并比较了三个Laves相（C15、C14和C36）的生成热。发现C15相是能量最低的基态结构，C36相是C15和C14之间的中间态。然而，这三个阶段，是非常接近的能量，表明在这个系统中的堆垛层错能量低。对于基态的C15，C14和C36相，我们计算了三个弹性常数，从中获得剪切模量和杨氏模量。结果发现，这些计算的模量C15是小于从多晶体获得的实验值。结构稳定性以C36、C14和C15的顺序增加，这也通过这些化合物的态密度得到了很好的解释。
The structural properties, elastic properties and electronic structures of TaCr{sub 2} are investigated by first-principles calculations. Heats of formation are calculated and compared for the three Laves phases (C15, C14 and C36). It is found that the C15 phase is the ground-state structure with the lowest energy and the C36 phase is an intermediate state between C15 and C14. These three phases, however, are very close in energy, indicating low stacking fault energies in this system. For the ground-state C15, C14 and C36 phases, we calculate three elastic constants from which the shear and Young's moduli are obtained. It is found that these calculated moduli of C15 are smaller than the experimental values obtained from polycrystals. The structural stability increases in the order C36, C14 and C15, which is also well explained through the densities of states of these compounds.