Du Xin, Zhang Jing, Yu Hong, Lin Jianyan, Zhang Shoutao, Yang Guochun
Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China.
Phys Chem Chem Phys. 2020 May 28;22(20):11460-11466. doi: 10.1039/d0cp01337d. Epub 2020 May 11.
Peroxides have attracted considerable attention due to their intriguing electronic properties and diverse applications. However, only a few transition metal peroxides have been known thus far, limiting the variety of peroxide examples. Here, we demonstrate the stabilization of peroxides in the O-rich V-O system through first-principles calculations coupled with a swarm-intelligence structure search. As well as reproducing the known stoichiometries of VO, VO, VO, and VO, two hitherto unknown VO and VO stoichiometries are predicted to be thermodynamically stable at megabar pressures. VO has the highest oxygen content among the known peroxides to date. More interestingly, its electronic band gap increases with pressure, originating from the pressure-induced decrease of O-O bonding length in the peroxide group. V-rich VO exhibits superconductivity, becoming the first example in the V-O system. Our work not only unravels the unusual vanadium peroxide, but also provides further insight into the diverse electronic properties of vanadium oxides under high pressure.
过氧化物因其引人入胜的电子性质和多样的应用而备受关注。然而，迄今为止已知的过渡金属过氧化物只有少数几种，限制了过氧化物实例的种类。在此，我们通过第一性原理计算结合群体智能结构搜索，证明了在富氧的V-O体系中过氧化物的稳定性。除了重现已知的VO、VO、VO和VO化学计量比外，预测两种迄今未知的VO和VO化学计量比在兆巴压力下具有热力学稳定性。VO是迄今为止已知过氧化物中氧含量最高的。更有趣的是，其电子带隙随压力增加，这源于过氧化物基团中O-O键长的压力诱导减小。富V的VO表现出超导性，成为V-O体系中的首个实例。我们的工作不仅揭示了不寻常的钒过氧化物，还为高压下钒氧化物的多样电子性质提供了进一步的见解。
