从头计算方法比较TiSi_2的C54相和C49相

Comparison between C54 and C49 Phase of TiSi_2 by ab initio Calculaltions

采用平面波超软赝势描述多电子体系,利用密度泛函理论和广义梯度近似,计算出C54相和C49相TiSi2的晶格常数、体弹性模量、形成能、电子态密度(DOS)和Mulliken电荷布居等性质.通过比较这两种物质的性质,发现尽管两者形成能很相近,但C49相结构对称性差、体弹性模量小、熔点低,Ti原子d轨道的反键强、离子性弱.这些性质上的差异和C49相TiSi2在固相反应中优先形成有关.

The ab initio plane-wave ultrasoft pseudopotential method based on generalized gradient approximation (GGA) has been utilized to compare C49 and C54 TiSi2 in terms of the structural, elastic and electronic properties. It has been and found out that C49 TiSi2 has less symmetry and smaller bulk modulus, lower melting point, stronger antibonding states above Femi level, weaker ionicity than C54 TiSi2, even though their formation energies are almost equal to each other.