中文摘要：

【目的】对 RE2 Ti3 Si4（RE＝Gd，Tb，Dy，Ho和 Er）的物理性能进行研究。【方法】利用基于密度泛函的第一性原理方法对 RE2 Ti3 Si4（RE＝Gd，Tb，Dy，Ho 和 Er）的结构性质、电子结构、力学以及热力学性质进行计算。对RE2 Ti3 Si4单晶的弹性常数，多晶的体积模量、剪切模量和杨氏模量都进行了计算。利用准谐的德拜模型计算获得了体积模量、比热熔和热膨胀系数随着温度和压强的变化，并进行了相关的讨论。【结果】RE2 Ti3 Si4的晶格常数计算值和实验值吻合较好。【结论】形成焓的计算值随着稀土元素原子序数的增加而呈现微小的下降趋势，这表明化合物的稳定性随着原子序数的增加而加强。电子态密度显示在费米能级之下，Ti-3d和 RE-5d的态密度有着很强的杂化现象。

英文摘要：

[Objective]Physical properties of the RE2 Ti3 Si4 （RE=Gd,Tb,Dy,Ho and Er）are studied.[Methods]We present the structural,electronic structure,mechanical and thermody-namic properties of the RE2 Ti3 Si4 （RE=Gd,Tb,Dy,Ho and Er）by using first-principles calcu-lations based on the density functional theory （DFT）.[Results]The calculated lattice constants of RE2 Ti3 Si4 are all in good agreement with experimental data.The single crystal elastic con-stants of RE2 Ti3 Si4 have been calculated,and the bulk,shear and Young＇s modulus are all been estimated in this work.Finally,using a quasi-harmonic Debye model,the bulk modulus,heat ca-pacity,and coefficient of thermal expansion have also been obtained and discussed.[Conclusion]The calculated formation enthalpies of the RE2 Ti3 Si4 show tiny decline trend with the increas-ing atomic number,which indicates that phase stability of RE2 Ti3 Si4 enhance slightly with in-creasing atomic number.The electronic densities of states indicate that Ti-3d and RE-5d peaks show strong hybridization below the Fermi level.