Ti2SiC在高压下结构、弹性和电子性质的第一性原理研究

采用第一性原理方法,研究了Ti_2SiC在高压下的结构、弹性和电子性质。结果表明,随着外压的增大,Ti_2SiC的晶格常数a、c和体积V均减小,且a比c减小幅度更大,表明Ti_2SiC在a轴方向比c轴方向更容易被压缩,体现了该材料的各向异性。计算分析了Ti_2SiC的弹性常数、体模量、剪切模量、杨氏模量、泊松比等弹性性质,这些弹性性质均随着外压的增加而增大,并根据弹性常数证明了Ti_2SiC在0~50GPa范围内均是力学稳定的。此外,还从电子态密度的角度考察了Ti_2SiC的电子性质,认为其具有共价键和金属键的双重性质,并发现在0~50GPa范围内压力对Ti_2SiC的态密度性质影响较小。

First-principles Study on the Structural, Elastic and Electronic Properties of Ti2SiC Under High Pressure

The structural, elastic and electronic properties of Ti₂SiC under high pressure were investigated by first-principles calculations. The results showed that the lattice parameters (a, c) and the unit cell volume (V) all decreased as a function of external pressure, and a changed more than c in the whole pressure range,which inferred that Ti₂SiC is more compressible in the a direction than c direction, and thus exhibits a certain anisotropicity. The elastic properties (C_ij, B and G) of Ti₂SiC were calculated, they all increase as pressure increases. The results revealed that Ti₂SiC is mechanically stable at pressure range of 0-50 GPa. The DOS of Ti₂SiC indicated that the bonding nature of Ti₂SiC is metallic combined with covalent, and pressure has no significant influence on the electronic properties of Ti₂SiC at 0 to 50 GPa.