论文标题
XC功能的依赖性以及CO（SI）的3s（2p）轨道作为COSI振动和热力学特性上的3s（2p）轨道的作用
Dependency of XC functionals and role of 3s(2p) orbitals of Co(Si) as core/valence states on the vibrational and thermodynamic properties of CoSi
论文作者
论文摘要
第一原理声子计算以及密度功能理论（DFT）在研究材料的动力学和热特性方面起着重要作用。在这里，我们研究了交换相关（XC）功能对COSI振动和热力学特性的影响。还研究了CO（2p）轨道作为核/价状态在该化合物的声子特性上的作用。使用从DFT计算获得的平衡晶体结构，通过有限位移方法使用有限位移方法进行了调子计算。将计算结果与现有实验进行比较。三个XC功能，即，LDA，PBESOL和扫描用于计算该化合物的声子分散，状态（DOS）/部分DOS的声子密度以及该化合物的热性能。发现扫描的最高声子频率为$ \ sim $ 56 meV，与实验值非常吻合，而LDA（PBESOL）给出$ \ sim $ 54（$ \ sim $ 55）MEV。对于所有功能，将零点的能量计算为$ \ sim $ 10 kJ/mol。 Debye温度（$θ_{D} $）分别计算为$ \ sim $ 626 K，$ \ sim $ 638 K和$ \ sim $ 650 K用于LDA，PBESOL和SCAN。从LDA获得的$θ_{D} $提供了与报告值的良好协议。发现声子分散和声子DOS是否依赖于CO（SI）的3s（2p）轨道是否被视为核心状态或价状态。但是，这种轨道依赖性似乎对这种化合物的热性质微不足道。
First-principles phonon calculations along with density functional theory (DFT) play an important role to study the dynamical and thermal properties of materials. Here, we investigate the effect of exchange correlation (XC) functionals on the vibrational and thermodynamic properties of CoSi. The role of 3s(2p) orbitals of Co(Si) as core/valence states on the phonon properties of this compound is also studied. Phonon calculations are carried out by finite displacement method with supercell approach using equilibrium crystal structures obtained from DFT calculations. The calculated results are compared with the existing experiment. Three XC functionals, viz., LDA, PBEsol and SCAN are used for calculating the phonon dispersion, phonon density of states (DOS)/partial DOS and thermal properties of this compound. SCAN is found to give the highest phonon frequency of $\sim$56 meV which is in good agreement with the experimental value, while LDA (PBEsol) gives $\sim$54 ($\sim$55) meV. The zero-point energy is calculated as $\sim$ 10 kJ/mol for all the functionals. The Debye temperatures ($Θ_{D}$) are computed as $\sim$626 K, $\sim$638 K and $\sim$650 K for LDA, PBEsol and SCAN, respectively. The $Θ_{D}$ obtained from LDA gives the good agreement with the reported value. The phonon dispersion and phonon DOS are found to be dependent whether 3s(2p) orbitals of Co(Si) are considered as core or valence states. But, this orbital dependency is seemed to be insignificant on the thermal properties of this compound.
