Sabbar Ehsan H, Al-Zubaidi Hazim A, Kurdi Aous H, Ibrahim Isam M, Ali Iftikhar M
Electrical Engineering, University of Anbar, Ramdi, Iraq.
Department of Medical Physics, Al-Karkh University of Science, Baghdad, Iraq.
J Mol Model. 2023 Aug 31;29(9):302. doi: 10.1007/s00894-023-05698-y.
This study rigorously investigates three 3d transition metal carbide (TMC) structures via LDA and GGA approximations. It examines cohesive energy (E), Vickers hardness (H), mechanical stability, and electronic properties. Notably, most 3d TMCs exhibit higher cohesive energy than nitrides, and rs-TiC demonstrates a Vickers hardness of 25.66 GPa, outperforming its nitride counterpart. The study employs theoretical calculations to expedite research, revealing mechanical stability in CrC and MnC (GGA) and CrC (LDA in cc structure), while all 3d TMCs in rs and seven in zb structures show stability. Charge transfer and bonding analysis reveal enhanced covalency along the series, influenced by the interplay between p orbitals of carbon and d orbitals of the metal. Most 3d TMCs exhibit metallic properties, excluding zb-TiC and zb-FeC in all phases. An inverse correlation between elastic constant C and electronic states near the Fermi level (E) emerges, guiding applications and design. This study efficiently uncovers 3d TMC properties, offering insights for applications and design.
We employed the Vienna ab initio Simulation software (VASP) to perform computations based on density functional theory (DFT). Our approach incorporated both the projector augmented wave (PAW) and PW91 general gradient approximation (GGA) methods within the local density approximation (LDA).
本研究通过LDA和GGA近似严格研究了三种三维过渡金属碳化物（TMC）结构。它考察了内聚能（E）、维氏硬度（H）、力学稳定性和电子性质。值得注意的是，大多数三维TMC的内聚能高于氮化物，rs-TiC的维氏硬度为25.66 GPa，优于其氮化物对应物。该研究采用理论计算来加速研究，揭示了CrC和MnC（GGA）以及cc结构中的CrC（LDA）的力学稳定性，而rs结构中的所有三维TMC和zb结构中的七种TMC都表现出稳定性。电荷转移和键合分析表明，受碳的p轨道与金属的d轨道之间相互作用的影响，沿该系列共价性增强。大多数三维TMC表现出金属性质，所有相中的zb-TiC和zb-FeC除外。弹性常数C与费米能级（E）附近的电子态之间出现反相关，为应用和设计提供了指导。本研究有效地揭示了三维TMC的性质，为应用和设计提供了见解。
我们使用维也纳从头算模拟软件（VASP）基于密度泛函理论（DFT）进行计算。我们的方法在局域密度近似（LDA）中纳入了投影增强波（PAW）和PW91广义梯度近似（GGA）方法。
