Abstract

From the beryllide group, NiBe is a hybrid material of CsCl (B2) type structure and presents a large range of stoichiometry. In this paper, we have studied the structural, electronic, elastic, and dynamic properties of NiBe intermetallic compound under pressure by performing ab initio density functional theory using the Cambridge Serial Total Energy Package (CASTEP). In B2 structure, we have obtained the lattice constant (\({A}_{\mathrm {0}}\)), equilibrium volume (\({V}_{\mathrm {0}}\)), bulk modulus (\({B}_{\mathrm {0}}\)) and its pressure derivative (\({B}_{0}\) ’) and elastic constants. We have quantitatively analyzed the band structure and the corresponding density of states (DOS). We have also estimated the mechanical stability and brittle/ductile behaviors of this compound based on the computed elastic constants. It is found that this structure is stable between 0 and 50 GPa pressure for NiBe compound. Finally, the changing degree of anisotropy with pressure was analyzed in three and two dimensions.

Graphic abstract

中文翻译：

---

金属间化合物NiBe在压力下的电子结构，弹性，动力学性质的理论研究

摘要

从铍化物组来看，NiBe是CsCl（B2）型结构的杂化材料，具有很大的化学计量比。在本文中，我们通过使用剑桥连续总能量包（CASTEP）进行了从头算密度函数理论研究了NiBe金属间化合物在压力下的结构，电子，弹性和动力学性质。在B2结构中，我们获得了晶格常数（\（{A} _ {\ mathrm {0}} \）），平衡体积（\（{V} _ {\ mathrm {0}} \）），体积模量（\（{B} _ {\ mathrm {0}} \））及其压力导数（\（{B} _ {0} \）'）和弹性常数。我们已经定量分析了能带结构和相应的状态密度（DOS）。我们还根据计算出的弹性常数估算了该化合物的机械稳定性和脆性/延性行为。发现对于NiBe化合物，该结构在0至50GPa压力下是稳定的。最后，从三个维度和两个维度分析了各向异性随压力的变化程度。

图形摘要