First-principles study of structural, elastic and lattice dynamical properties of chalcopyrite BeSiV2 and MgSiV2 (V = P, As, Sb)
First-principles study of structural, elastic and lattice dynamical properties of chalcopyrite BeSiV2 and MgSiV2 (V = P, As, Sb)
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DOI：
10.1016/j.jallcom.2014.05.031
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发表时间：
2014-10
影响因子：
6.2
通讯作者：
Liwei Shi;Jingzu Hu;Yun Qin;Y. Duan;Ling Wu;Xian-qing Yang;G. Tang
中科院分区：
文献类型：
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作者：
Liwei Shi;Jingzu Hu;Yun Qin;Y. Duan;Ling Wu;Xian-qing Yang;G. Tang
利用范数守恒赝势和广义梯度近似，在密度泛函理论中对黄铜矿bessiv2和mgsiv2 （V= P, As, Sb）的结构、弹性和晶格动力学性质进行了第一性原理计算。所得的平衡结构参数与已有的实验和理论结果吻合较好。对单晶弹性常数、线压缩率和体积压缩率、剪切各向异性因子、多晶体积、剪切模量、杨氏模量和泊松比进行了预测。结果表明，与BeSiV 2相比，MgSiV 2化合物在压缩和剪切过程中具有更明显的四方畸变和更大的弹性各向异性。黄铜矿bessiv 2和MgSiV 2分别属于脆性和延展性材料。用线性响应法计算了声子色散关系、声子态密度、红外吸收光谱和拉曼散射光谱。此外，还详细分析了区域中心Γ点拉曼有源（E, b2， b1和a1）、红外有源（E和b2）和无源（a2）模式的声子频率和原子位移图。振动谱的特征受结构单元的化学键强度和质量的共同支配。此外，在MgSiV - 2黄铜矿半导体中，Si-V成键明显强于Mg-V成键。
First-principles calculations of the structural, elastic and lattice dynamical properties of chalcopyrite BeSiV 2 and MgSiV 2 (V= P, As, Sb) have been performed within density functional theory using norm-conserving pseudopotentials and generalized-gradient approximation. The obtained equilibrium structural parameters are in good agreement with available experimental and theoretical results. Single-crystal elastic constants, linear and volume compressibilities, shear anisotropic factors, as well as polycrystalline bulk, shear and Young’s modulus and Poisson’s ratio have been predicted. Our results show that, compared with BeSiV 2, more pronounced tetragonal distortion and larger elastic anisotropy in both compression and shear have been found in MgSiV 2 compounds. Chalcopyrite BeSiV 2 and MgSiV 2 have been classified as brittle and ductile materials, respectively. Phonon dispersion relations, phonon density of states, infrared absorption spectra and Raman scattering spectra have been calculated using the linear response method. Besides, the phonon frequencies and atomic displacement patterns for Raman-active (E, B 2, B 1 and A 1), infrared-active (E and B 2), and silent (A 2) modes at zone-center Γ point have been analyzed in detail. The character of vibrational spectra have been found to be governed by both chemical bonding strengths and masses of structural units. Moreover, the Si–V bonding is remarkably stronger than the Mg–V bonding in MgSiV 2 chalcopyrite semiconductors.