Photo-induced semimetallic states realised in electron-hole coupled insulators

Abstract

Using light to manipulate materials into desired states is one of the goals in condensed matter physics, since light control can provide ultrafast and environmentally-friendly photonics devices. However, it is generally difficult to realise a photo-induced phase which is not merely a higher entropy phase corresponding to a high-temperature phase at equilibrium. Here, we report realization of photo-induced insulator-to-metal transitions in Ta2Ni(Se1-xSx)5 including the excitonic insulator phase using time- and angle-resolved photoemission spectroscopy. From the dynamic properties of the system, we determine that screening of excitonic correlations plays a key role in the timescale of the transition to the metallic phase, which supports the existence of an excitonic-insulator phase at equilibrium. The non-equilibrium metallic state observed unexpectedly in the direct-gap excitonic insulator opens up a new avenue to optical band engineering in electron-hole coupled systems.

References in corpus (15)

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• Signatures of exciton condensation in a transition metal dichalcogenide
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• Coherent Phonon Coupling to Individual Bloch States in Photoexcited Bismuth
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• Direct characterization of photo-induced lattice dynamics in BaFe2As2
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Cited by in corpus (54)

• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Direct observation of excitonic instability in Ta2NiSe5
• Band hybridisation at the semimetal-semiconductor transition of Ta${}_2$NiSe${}_5$ enabled by mirror-symmetry breaking
• Non-Coulomb strong electron-hole binding in $T{a}_{2}NiS{e}_5$ revealed by time- and angle-resolved photoemission spectroscopy
• Imaging the coherent propagation of collective modes in the excitonic insulator candidate Ta${}_2$NiSe${}_5$ at room temperature
• Collective Modes in Excitonic Insulators: Effects of Electron-Phonon Coupling and Signatures in Optical Response
• Detecting electron-phonon couplings during photo-induced phase transition
• Self-similar dynamics of order parameter fluctuations in pump-probe experiments
• Orthorhombic-to-monoclinic transition in Ta${}_2$NiSe${}_5$ due to a zone-center optical phonon instability
• Ultrafast melting and recovery of collective order in the excitonic insulator Ta${}_2$NiSe${}_5$
• Phononic soft mode and strong electronic background behavior across the structural phase transition in the excitonic insulator Ta${}_2$NiSe${}_5$ (with Erratum)
• Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
• Ultrafast nonequilibrium evolution of excitonic modes in semiconductors
• Photo-induced phase transition and associated time scales in the excitonic insulator Ta${}_2$NiSe${}_5$
• Role of electron-phonon coupling in excitonic insulator candidate Ta2NiSe5
• Hybridization-gap Formation and Superconductivity in the Pressure-induced Semimetallic Phase of the Excitonic Insulator Ta${}_2$NiSe${}_5$
• The critical role of hot carrier cooling in optically excited structural transitions
• A New Era of Excitonic Insulators
• Nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators
• Nonlinear spectroscopy of collective modes in excitonic insulator
• Disentangling lattice and electronic instabilities in the excitonic insulator candidate Ta${}_2$NiSe${}_5$ by nonequilibrium spectroscopy
• Signatures of ultrafast reversal of excitonic order in Ta${}_2$NiSe${}_5$
• Unveiling the underlying interactions in Ta2NiSe5 from photo-induced lifetime change
• Nonequilibrium dynamics in pumped Mott insulators
• Ultrafast Switching from the Charge Density Wave Phase to a Metastable Metallic State in 1T-TiSe${}_2$
• Evidence for an Excitonic Insulator State in Ta${}_2$Pd${}_3$Te${}_5$
• HHG-laser-based time- and angle-resolved photoemission spectroscopy of quantum materials
• Photoinduced electron-electron pairing in the extended Falicov-Kimball model
• Ultrafast charge carrier and exciton dynamics in an excitonic insulator probed by time-resolved photoemission spectroscopy
• Tunneling-tip-induced collapse of the charge gap in the excitonic insulator Ta${}_2$NiSe${}_5$
• Evolution of the electronic structure in Ta${}_2$NiSe${}_5$ across the structural transition revealed by resonant inelastic x-ray scattering
• Finite-temperature photoemission in the extended Falicov-Kimball model: a case study for Ta${}_2$NiSe${}_5$
• Thermal transport signatures of the excitonic transition and associated phonon softening in the layered chalcogenide Ta${}_2$NiSe${}_5$
• Effects of Disorder on the Transport of Collective Modes in an Excitonic Condensate
• Photoinduced metallization of excitonic insulators
• Pressure suppression of the excitonic insulator state in Ta2NiSe5 observed by optical conductivity
• Third-harmonic generation in excitonic insulators
• Phase-resolved frequency-domain analysis of the photoemission spectra for photoexcited 1T-TaS2 in the Mott insulating charge density wave state
• Direct observation of multiple conduction-band minima in high-performance thermoelectric SnSe
• Collective modes and Raman response in Ta${}_2$NiSe${}_5$
• Photo-excitation band-structure engineering of 2H-NbSe${}_2$ probed by time- and angle-resolved photoemission spectroscopy
• Light-induced switching of magnetic order in the anisotropic triangular-lattice Hubbard model
• FFLO Superconductivity Mediated by Excitonic Fluctuation in Semimetallic Ta${}_2$NiSe${}_5$
• Time- and angle-resolved photoemission spectroscopy with wavelength-tunable pump and extreme ultraviolet probe enabled by twin synchronized amplifiers
• Photoinduced dynamics of excitonic order and Rabi oscillation in the two-orbital Hubbard model
• Detecting photoelectrons from spontaneously formed excitons
• Photo-induced Dynamics of Quasicrystalline Excitonic Insulator
• Gate tuning of coupled electronic and structural phase transition in atomically thin Ta${}_2$NiSe${}_5$
• Time-Resolved Photoemission Spectroscopy of Quantum Materials Using High Harmonic Generation: Probing Electron-Phonon Interactions and Non-Equilibrium Dynamics
• Photo-induced nonlinear band shift and valence transition in SmS
• Using magnetic dynamics to measure the spin gap in a candidate Kitaev material
• Photoinduced pairing in Mott insulators
• Nonequilibrium Dynamics in a Quantum Spin Chain with Pump-Probe Resonant Inelastic X-ray Scattering
• Probing the collective excitations of excitonic insulators in an optical cavity