Ultrafast Switching from the Charge Density Wave Phase to a Metastable Metallic State in 1T-TiSe${}_2$

Abstract

The ultrafast electronic structures of the charge density wave material 1T-TiSe${}_2$ were investigated by high-resolution time- and angle-resolved photoemission spectroscopy. We found that the quasiparticle populations drove ultrafast electronic phase transitions in 1T-TiSe${}_2$ within 100 fs after photoexcitation, and a metastable metallic state, which was significantly different from the equilibrium normal phase, was evidenced far below the charge density wave transition temperature. Detailed time- and pump-fluence-dependent experiments revealed that the photoinduced metastable metallic state was a result of the halted motion of the atoms through the coherent electron-phonon coupling process, and the lifetime of this state was prolonged to picoseconds with the highest pump fluence used in this study. Ultrafast electronic dynamics were well captured by the time-dependent Ginzburg-Landau model. Our work demonstrates a mechanism for realizing novel electronic states by photoinducing coherent motion of atoms in the lattice.

13 Pages, 10 figures

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Cited by in corpus (9)

• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• A New Era of Excitonic Insulators
• Ultrafast creation of a light induced semimetallic state in strongly excited 1T-TiSe${}_2$
• Momentum-Resolved Signatures of Carrier Screening Effects on Electron-Phonon Coupling in MoS${}_2$
• Time-domain study of coupled collective excitations in quantum materials
• Identification of metastable lattice distortion free charge density wave at photoinduced interface via TRARPES
• Electron-phonon-dominated charge-density-wave fluctuations in TiSe${}_2$ accessed by ultrafast nonequilibrium dynamics
• Fate of transient order parameter domain walls in ultrafast experiments
• Revisiting the charge-density-wave superlattice of 1$T$-TiSe${}_2$