Guo Feng-Wu, Liu Wen-Hao, Wang Zhi, Li Shu-Shen, Wang Lin-Wang, Luo Jun-Wei
State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2025 Jan 2;16(1):94. doi: 10.1038/s41467-024-55760-3.
The insulator-to-metal transition in VO has garnered extensive attention for its potential applications in ultrafast switches, neuronal network architectures, and storage technologies. However, the photoinduced insulator-to-metal transition remains controversial, especially whether a complete structural transformation from the monoclinic to rutile phase is necessary. Here we employ the real-time time-dependent density functional theory to track the dynamic evolution of atomic and electronic structures in photoexcited VO, revealing the emergence of a long-lived monoclinic metal phase under low electronic excitation. The emergence of the metal phase in the monoclinic structure originates from the dissociation of the local V-V dimer, driven by the self-trapped and self-amplified dynamics of photoexcited holes, rather than by an electron-electron correction. On the other hand, the monoclinic-to-rutile phase transition does appear at higher electronic excitation. Our findings validate the existence of monoclinic metal phase and provide a comprehensive picture of the insulator-to-metal transition in photoexcited VO.
VO中的绝缘体-金属转变因其在超快开关、神经网络架构和存储技术中的潜在应用而备受关注。然而，光致绝缘体-金属转变仍存在争议，尤其是从单斜相到金红石相的完全结构转变是否必要。在这里，我们采用实时含时密度泛函理论来追踪光激发VO中原子和电子结构的动态演化，揭示了在低电子激发下长寿命单斜金属相的出现。单斜结构中金属相的出现源于局部V-V二聚体的解离，这是由光激发空穴的自陷和自放大动力学驱动的，而不是由电子-电子相互作用引起的。另一方面，在更高的电子激发下确实会出现单斜相到金红石相的转变。我们的发现证实了单斜金属相的存在，并提供了光激发VO中绝缘体-金属转变的全面图景。
