Dramatic Plasmon Response to the Charge-Density-Wave Gap Development in $1\text{T}-{\mathrm{TiSe}}_2$

Abstract

1T-TiSe2 is one of the most studied charge density wave (CDW) systems, not only because of its peculiar properties related to the CDW transition, but also due to its status as a promising candidate of exciton insulator signaled by the proposed plasmon softening at the CDW wave vector. Using high-resolution electron energy loss spectroscopy, we report a systematic study of the temperature-dependent plasmon behaviors of 1T-TiSe2. We unambiguously resolve the plasmon from phonon modes, revealing the existence of Landau damping to the plasmon at finite momentums, which does not support the plasmon softening picture for exciton condensation. Moreover, we discover that the plasmon lifetime at zero momentum responds dramatically to the bandgap evolution associated with the CDW transition. The interband transitions near the Fermi energy in the normal phase is demonstrated serving as a strong damping channel of plasmons, while such a channel in the CDW phase is suppressed due to the CDW gap opening, which results in the dramatic tunability of the plasmon in semimetals or small-gap semiconductors.

References in corpus (20)

• Evidence for an excitonic insulator phase in 1T-TiSe${}_2$
• Signatures of exciton condensation in a transition metal dichalcogenide
• Classification of Charge Density Waves Based on Their Nature
• Non-thermal separation of electronic and structural orders in a persisting charge density wave
• Semimetal to semimetal charge density wave transition in 1T-TiSe${}_2$
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• Revealing the role of electrons and phonons in the ultrafast recovery of charge density wave correlations in 1$T$-TiSe${}_2$
• Impact of Electron-Hole Correlations on the 1T-TiSe2 Electronic Structure
• Short-range phase coherence and origin of the 1T-TiSe2 charge density wave
• An Alternative Interpretation of Recent ARPES Measurements on TiSe2
• Fermi surface reconstruction and electron dynamics at the charge-density-wave transition in TiSe2
• Exciton-phonon interactions and superconductivity bordering charge order in TiSe2
• Charge Density Wave Hampers Exciton Condensation in 1T-TiSe${}_2$
• Excitonic insulator emerging from semiconducting normal state in $1T$-TiSe${}_2$

Cited by in corpus (13)

• A New Era of Excitonic Insulators
• Unconventional Thermophotonic Charge Density Wave
• Excitonic Instability in Ta2Pd3Te5 Monolayer
• A Pathway to Efficient Simulations of Charge Density Waves in Transition Metal Dichalcogenides: A Case Study for TiSe2
• Superconductivity in 2D systems enhanced by nonadiabatic phonon-production effects
• Interlayer Hopping between Surface Mott Insulator and Bulk Band Insulator in layered 1T-TaS_{2}
• Persistence of charge ordering instability to Coulomb engineering in the excitonic insulator candidate TiSe${}_2$
• Electron-phonon-dominated charge-density-wave fluctuations in TiSe${}_2$ accessed by ultrafast nonequilibrium dynamics
• Cluster charge-density-wave glass in hydrogen-intercalated TiSe${}_2$
• Plasmonic polaron in self-intercalated 1T-TiS2
• Revisiting the charge-density-wave superlattice of 1$T$-TiSe${}_2$
• Direct evidence for two-gap superconductivity in hydrogen-intercalated titanium diselenide
• Excitons and Optical Response in Excitonic Insulator Candidate TiSe${}_2$