一种超硬新材料BeP 2 N 4 的电子结构和力学性质及本征硬度
一种超硬新材料BeP 2 N 4 的电子结构和力学性质及本征硬度
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DOI：
10.3866/pku.whxb20110730
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发表时间：
2011-06
期刊：
影响因子：
--
通讯作者：
丁迎春;肖冰
中科院分区：
文献类型：
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作者：
丁迎春;肖冰
采用第一性原理计算方法研究了晶体结构、能带结构、态密度、偏态密度、本文采用广义梯度近似（GGA）和局域密度近似（LDA）计算了BeP_2N_4的Mulliken布居和弹性性质，计算结果与实验数据和其它理论计算结果符合得很好，并对BeP_2N_4的电子结构进行了讨论。4表明它们是具有宽带隙的绝缘体。尖晶石结构的机械模量大于非钠闪石结构的机械模量。根据Sung和Gao等人提出的方法评估了两种多晶型的硬度。虽然非钠闪石的体积模量很小，但结果表明它是一种相对较硬的材料。另一方面，尖晶石结构是一种超硬相，随着压力的增加，非钠闪石结构逐渐具有延展性，计算得到的非钠闪石向尖晶石转变的GGA压力为14 GPa，小于预测值24 GPa。
First-principles calculations were carried out to investigate the crystal structures,band structure,density of states,partial densities of states,Mulliken population and elastic properties of two BeP_2N_4 polymorphs namely phenakite and spinel.The generalized gradient approximation(GGA) and local density approximation(LDA) were used.The calculated results agree well with the experimental data and other theoretical calculations.The electronic structures of BeP_2N_4 indicate that they are insulators with wide bandgaps.The mechanical moduli of the spinel structure are larger than that of phenakite.The hardness of the two polymorphs was evaluated based on the methods proposed by Sung and Gao et al.Although the bulk modulus of phenakite is small the results indicate that it is a relatively hard material.On the other hand,the spinel structure is a super hard phase.When the pressure increases the phenakite structure gradually becomes malleable.The calculated GGA transition pressure from phenakite to spinel is 14 GPa, which is smaller than the predicted value of 24 GPa.