Metal–Metal Bonding Stabilized Ground State Structure of Early Transition Metal Monoxide TM–MO (TM = Ti, Hf, V, Ta)
详细信息 查看全文
- 作者：Linggang Zhu ; Jian Zhou ; Zhonglu Guo ; Zhimei Sun
- 刊名：Journal of Physical Chemistry C
- 出版年：2016
- 出版时间：May 12, 2016
- 年：2016
- 卷：120
- 期：18
- 页码：10009-10014
- 全文大小：399K
- 年卷期：0
- ISSN：1932-7455
文摘
It is commonly believed that early transition metal monoxides (TM–MOs) crystallize in simple rock-salt structures (symmetry FM3̅M) for their ground states. Here, by combining structure-searching algorithm and first-principles calculations, we identified structures that are more stable than the ideal rock-salt for the early TM–MOs (TM = Ti, Hf, V, Ta). For TiO, HfO, and TaO, ground state symmetries of P6̅2M), I41/AMD and P1̅ are obtained, respectively, which have distinct structural and electronic properties compared to the rock-salt structure. However, it is rather complex for the case of VO due to the existence of magnetic ordering. For VO, magnetic ordering behavior exists in the rock-salt and the predicted P1̅ structure according to the hybrid functional calculations. After relaxation, the magnetic ordering causes local distortion in the original rock-salt structure, leading to a R3̅M symmetry, which becomes more stable than the predicted P1̅ structure. Furthermore, the ionic TM–O bonding of the predicted phases is rather weaker than that of their rock-salt counterparts. While the enhanced metal–metal bonding characterized by the distances between the nearest-neighboring metallic atoms is found to be responsible for the stabilization of the ground state structures discovered here. Our findings deepen the understanding of the ground state of early TM–MOs, which is vital for the unraveling of the complete physical picture for transition metal monoxides.