The photoinduced hidden metallic phase of monoclinic VO2 driven by local nucleation via a self-amplification process

Abstract

The insulator-to-metal transition (IMT) in vanadium dioxide (VO2) has garnered extensive attention for its potential applications in ultrafast switches, neuronal network architectures, and storage technologies. However, a significant controversy persists regarding the formation of the IMT, specifically concerning whether a complete structural phase transition from monoclinic (M1) to rutile (R) phase is necessary. Here we employ the real-time time-dependent density functional theory (rt-TDDFT) to track the dynamic evolution of atomic and electronic structures in photoexcited VO2, revealing the emergence of a long-lived monoclinic metal phase (MM) 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 a pure electron-electron correction. On the other hand, the M1-to-R phase transition does appear at higher electronic excitation. Our findings validate the existence of MM phase and provide a comprehensive picture of the IMT in photoexcited VO2.

34 pages, 18 figures

References in corpus (10)

• Evidence for a Structurally-driven Insulator-to-metal Transition in VO2: a View from the Ultrafast Timescale
• Electronic Defects in Metal Oxide Photocatalysts
• Orbital-assisted metal-insulator transition in VO${}_2$
• Universal phase dynamics in VO2 switches revealed by ultrafast operando diffraction
• Optical Stabilization of Fluctuating High Temperature Ferromagnetism in YTiO${}_3$
• Transient dynamics of the phase transition in VO2 revealed by mega electron-volt ultrafast electron diffraction
• The seeds and homogeneous nucleation of photoinduced nonthermal melting in semiconductors due to self-amplified local dynamic instability
• Uniting the order and disorder dynamics in photoexcited VO2
• Ultrafast lattice disordering can be accelerated by electronic collisional forces
• All-optical seeding of a light-induced phase transition with correlated disorder