Signatures of exciton condensation in a transition metal dichalcogenide

Abstract

Bose condensation has shaped our understanding of macroscopic quantum phenomena, having been realized in superconductors, atomic gases, and liquid helium. Excitons are bosons that have been predicted to condense into either a superfluid or an insulating electronic crystal. Using the recently developed momentum-resolved electron energy-loss spectroscopy (M-EELS), we study electronic collective modes in the transition metal dichalcogenide semimetal, 1T-TiSe${}_2$. Near the phase transition temperature, T${}_c$ = 190 K, the energy of the electronic mode falls to zero at nonzero momentum, indicating dynamical slowing down of plasma fluctuations and crystallization of the valence electrons into an exciton condensate. Our study provides compelling evidence for exciton condensation in a three-dimensional solid and establishes M-EELS as a versatile technique sensitive to valence band excitations in quantum materials.

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• Measurement of the dynamic charge response of materials using low-energy, momentum-resolved electron energy-loss spectroscopy (M-EELS)
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Cited by in corpus (222)

• Evidence of high-temperature exciton condensation in 2D atomic double layers
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• Strongly correlated excitonic insulator in atomic double layers
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• Evidence for a Monolayer Excitonic Insulator
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• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Superradiant Quantum Materials
• Nature of symmetry breaking at the excitonic insulator transition: Ta${}_2$NiSe${}_5$
• Optical detection and manipulation of spontaneous gyrotropic electronic order in a transition-metal dichalcogenide semimetal
• Raman spectrum of Janus transition metal dichalcogenide monolayers WSSe and MoSSe
• Discovery of a Cooper-Pair Density Wave State in a Transition-Metal Dichalcogenide
• Photo-induced semimetallic states realised in electron-hole coupled insulators
• Direct observation of excitonic instability in Ta2NiSe5
• Orbital- and $k_z$-selective hybridisation of Se 4p and Ti 3d states in the charge density wave phase of TiSe${}_2$
• Optical manipulation of electronic dimensionality in a quantum material
• Correlated electron-hole State in Twisted Double Bilayer Graphene
• Photoemission signature of excitons
• Condensation signatures of photogenerated interlayer excitons in a van der Waals heterostack
• Electronic, optical and transport properties of van der Waals Transition-metal Dichalcogenides Heterostructures: A First-principle Study
• Band hybridisation at the semimetal-semiconductor transition of Ta${}_2$NiSe${}_5$ enabled by mirror-symmetry breaking
• General corner charge formula in two-dimensional C_n-symmetric higher-order topological insulators
• Mechanisms of electron-phonon coupling unraveled in momentum and time: The case of soft-phonons in TiSe${}_2$
• Spin-Triplet Excitonic Insulator: The Case of Graphone
• Reproduction of the charge density wave phase diagram in $1T$-${\mathrm{TiSe}}_2$ exposes its excitonic character
• Geometry of the charge density wave in kagom$\acute{e}$ metal AV${}_3$Sb${}_5$
• Weak Dimensionality Dependence and Dominant Role of Ionic Fluctuations in the Charge-Density-Wave Transition of NbSe${}_2$
• Excitonic and lattice contributions to the charge density wave in 1T-TiSe${}_2$ revealed by a phonon bottleneck
• Strong interband interaction in the excitonic insulator phase of Ta${}_2$NiSe${}_5$
• Bilayer WSe${}_2$ as a natural platform for interlayer exciton condensates in the strong coupling limit
• Highly Confined In-plane Exciton-Polaritons in Monolayer Semiconductors
• 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
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• Morphology Control of Epitaxial Monolayer Transition Metal Dichalcogenides
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• Evidence of high-temperature exciton condensation in a two-dimensional semimetal
• Fermi surface reconstruction and electron dynamics at the charge-density-wave transition in TiSe2
• Light-induced dimension crossover in 1T-TiSe${}_2$ dictated by excitonic correlations
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• Pump driven normal-to-excitonic insulator transition: Josephson oscillations and signatures of BEC-BCS crossover in time-resolved ARPES
• Collective Modes in Excitonic Magnets: Dynamical Mean-Field Study
• Exciton-Phonon Coupling and Band-Gap Renormalization in Monolayer WSe${}_2$
• Coexistence of resistance oscillations and the anomalous metal phase in a lithium intercalated TiSe${}_2$ superconductor
• Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
• Evidence of ideal excitonic insulator in bulk MoS2 under pressure
• Bulk Photovoltaic Effect Driven by Collective Excitations in a Correlated Insulator
• Preparation of an Exciton Condensate of Photons on a 53-Qubit Quantum Computer
• Magnon-mediated exciton-exciton interaction in a van der Waals antiferromagnet
• Few-body systems in condensed matter physics
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• Excitonic effects in two-dimensional TiSe${}_2$ from hybrid density functional theory
• Role of electron-phonon coupling in excitonic insulator candidate Ta2NiSe5
• Excitonic Instability and Electronic Property of Two-dimensional AlSb Limit
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• Exciton-Driven Renormalization of Quasiparticle Band Structure in Monolayer MoS2
• Semiconductor-metal phase transition and emergent charge density waves in 1T-ZrX${}_2$ (X = Se, Te) at the two-dimensional limit
• Extended spatial coherence of interlayer excitons in MoSe${}_2$/WSe${}_2$ heterobilayers
• Possible Excitonic Insulating Phase in Quantum-Confined Sb Nanoflakes
• Effect of Cu intercalation and pressure on excitonic interaction in 1T-TiSe2
• Orbital-selective Band Hybridisation at the Charge Density Wave Transition in Monolayer TiTe${}_2$
• Robust high-temperature topological excitonic insulator of transition-metal carbides (MXenes)
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• Effect of synthesis conditions on the electrical resistivity of TiSe${}_2$
• A New Era of Excitonic Insulators
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• Signatures of ultrafast reversal of excitonic order in Ta${}_2$NiSe${}_5$
• Charge Density Wave Hampers Exciton Condensation in 1T-TiSe${}_2$
• Topological excitonic corner states and nodal phase in bilayer quantum spin Hall insulators
• Theory of competing excitonic orders in insulating WTe${}_2$ monolayers
• Observation of possible excitonic charge density waves and metal-insulator transitions in atomically thin semimetals
• Theory of topological exciton insulators and condensates in flat Chern bands
• Antiferromagnetic Excitonic Insulator State in Sr3Ir2O7
• Precursors to Exciton Condensation in Quantum Hall Bilayers
• Structurally assisted melting of excitonic correlations in 1T-TiSe2
• Exciton-phonon-scattering: A competition between bosonic and fermionic nature of bound electron-hole pairs
• Functions to map photoelectron distributions in a variety of setups in angle-resolved photoemission spectroscopy
• Ultrafast Switching from the Charge Density Wave Phase to a Metastable Metallic State in 1T-TiSe${}_2$
• Coexisting charge-ordered states with distinct driving mechanisms in monolayer VSe${}_2$
• Bardasis-Schrieffer polaritons in excitonic insulators
• Energy-dependent spatial texturing of the charge order in $1T$-Cu${}_x$TiSe${}_2$
• Intrinsic Insulating Ground State in Transition Metal Dichalcogenide TiSe2
• Correlation between electronic and structural orders in 1T-TiSe2
• Adiabatic Preparation of a Correlated Symmetry-Broken Initial State with the Generalized Kadanoff--Baym Ansatz
• Leaky exciton condensates in transition metal dichalcogenide moiré bilayers
• Geometric Stiffness in Interlayer Exciton Condensates
• Electronic structure of TiSe${}_2$ from a quasi-self-consistent G${}_0$W${}_0$ approach
• Anomalous excitonic phase diagram in band-gap-tuned Ta2Ni(Se,S)5
• Spontaneous gap opening and potential excitonic states in an ideal Dirac semimetal Ta${}_2$Pd${}_3$Te${}_5$
• Terahertz parametric amplification as a reporter of exciton condensate dynamics
• Collective excitations of the U(1)-symmetric exciton insulator in a cavity
• Work function seen with sub-meV precision through laser photoemission
• Using Electron Energy-Loss Spectroscopy to Measure Nanoscale Electronic and Vibrational Dynamics in a TEM
• Topological charge pumping in excitonic insulators
• Cooper-Pair Condensates with Non-Classical Long-Range Order on Quantum Devices
• Evidence for an Excitonic Insulator State in Ta${}_2$Pd${}_3$Te${}_5$
• Potential Coexistence of Exciton and Fermion Pair Condensations
• Ultrafast dynamics in normal and Charge Density Wave phase of 2H-NbSe2
• Configurational Electronic States in Layered Metallic Dichalcogenides
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• Critical point for Bose-Einstein condensation of excitons in graphite
• Evidence for nesting driven charge density waves instabilities in a quasi-two-dimensional material: LaAgSb2
• Excitonic insulator emerging from semiconducting normal state in $1T$-TiSe${}_2$
• Intrinsic control of interlayer exciton generation rate in van der Waals materials via Janus layers
• Observation of orbital order in the Van der Waals material 1T-TiSe2
• Electron correlations rule the phonon-driven instability in single layer TiSe${}_2$
• Ultrafast charge carrier and exciton dynamics in an excitonic insulator probed by time-resolved photoemission spectroscopy
• Charge Density Wave Activated Excitons in TiSe${}_2$-MoSe${}_2$ Heterostructures
• Keldysh field theory of dynamical exciton condensation transitions in nonequilibrium electron-hole bilayers
• A gate-tunable quantum phase transition in a topological excitonic insulator
• Failed excitonic quantum phase transition in Ta${}_2$Ni(Se${}_{1-x}$S${}_x$)${}_5$
• BCS-BEC crossover in a $(t_{2g}{)}^4$ Excitonic Magnet
• Transition from band insulator to excitonic insulator via alloying Se into Monolayer TiS${}_3$: A Computational Study
• Elemental chalcogens as a minimal model for chiral charge and orbital order
• Kuramoto synchronization of quantum tunneling polarons for describing the dynamic structure in cuprate superconductors
• Evolution of the electronic structure in Ta${}_2$NiSe${}_5$ across the structural transition revealed by resonant inelastic x-ray scattering
• Lattice fluctuations, not excitonic correlations, mediated electronic localization in TiSe${}_2$
• Charge density waves and Fermi level pinning in monolayer and bilayer SnSe${}_2$
• Large Cumulant Eigenvalue as a Signature of Exciton Condensation
• Fermi edge singularity in neutral electron-hole system
• Thermal transport signatures of the excitonic transition and associated phonon softening in the layered chalcogenide Ta${}_2$NiSe${}_5$
• Beginnings of Exciton Condensation in Coronene Analog of Graphene Double Layer
• Effects of Disorder on the Transport of Collective Modes in an Excitonic Condensate
• Electronic band structures of topological kagome materials
• Two-particle spectral function for disordered s-wave superconductors: local maps and collective modes
• Biexciton Condensation in Electron-hole Doped Hubbard Bilayers -- A Sign-Problem-Free Quantum Monte Carlo Study
• Charge-Neutral Electronic Excitations in Quantum Insulators
• A Pathway to Efficient Simulations of Charge Density Waves in Transition Metal Dichalcogenides: A Case Study for TiSe2
• In-plane magnetic field induced density wave states near quantum spin Hall phase transitions
• Precursor phase with full phonon softening above the charge-density-wave phase transition in $2H$-TaSe${}_2$
• Excitonic Instability in Ta2Pd3Te5 Monolayer
• Dynamical response and competing orders in two-band Hubbard model
• Trigonal-to-monoclinic structural transition in TiSe${}_2$ due to a combined condensation of $\text{q}=(\frac{1}{2},0,0)$ and $(\frac{1}{2},0,\frac{1}{2})$ phonon instabilities
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• Ultrafast creation and melting of nonequilibrium excitonic condensates in bulk WSe${}_2$
• Entangled phase of simultaneous fermion and exciton condensations realized
• Geometric Effect of High-Resolution Electron Energy Loss Spectroscopy on the Identification of Plasmons: An Example of Graphene
• Mapping the dispersion of the occupied and unoccupied band structure in photoexcited 1T-TiSe${}_2$
• Perturbation of charge density waves in 1T-TiSe${}_2$
• Magnetization dynamics fingerprints of an excitonic condensate $t_{2g}^4$ magnet
• Hidden excitonic quantum states with broken time-reversal symmetry
• Plasmonic Waveguides from Coulomb-Engineered Two-Dimensional Metals
• Exciton and light induced ferromagnetism from doping a moiré Mott insulator
• Lifshitz transition enabling superconducting dome around the quantum critical point in TiSe${}_2$
• Simultaneous fermion and exciton condensations from a model Hamiltonian
• Collective modes and Raman response in Ta${}_2$NiSe${}_5$
• Superconductivity in 2D systems enhanced by nonadiabatic phonon-production effects
• Carrier-Density Control of the Quantum-Confined 1$T$-TiSe${}_2$ Charge-Density-Wave
• Excitonic insulators and superfluidity in 2D bilayers without external fields
• Excitonic Order and Superconductivity in the Two-Orbital Hubbard Model: Variational Cluster Approach
• Impact ionization dynamics in small band-gap 2D materials from a coherent phonon mechanism
• Long-lived population inversion in resonantly driven excitonic antiferromagnet
• Mott-Enhanced Exciton Condensation in a Hubbard bilayer
• Optically induced symmetry breaking due to nonequilibrium steady state formation in charge density wave material 1T-TiSe2
• Excitonic Metal and Non-Fermi Liquid Behaviour in Twisted Double Bilayer Graphene near Charge Neutrality
• Transition to an excitonic insulator from a two-dimensional conventional insulator
• Tightly-bound and room-temperature-stable excitons in van der Waals degenerate-semiconductor Bi4O4SeCl2 with high charge-carrier density
• 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${}_2$
• First-principles design of excitonic insulators: A review
• Thermal effects on collective modes in disordered $s$-wave superconductors
• In-plane anisotropy of charge density wave fluctuations in 1$T$-TiSe${}_2$
• Quantum Transport Properties of an Exciton Insulator/Superconductor Hybrid Junction
• Ultrafast melting of charge-density wave fluctuations at room temperature in $1T-TiS{e}_2$ monitored under non-equilibrium conditions
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• Realization of graphene logics in an exciton-enhanced insulating phase
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• Stable phases of freestanding monolayer TiO${}_2$: The emergence of out-of-plane ferroelectricity
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• Detecting photoelectrons from spontaneously formed excitons
• Photo-induced Dynamics of Quasicrystalline Excitonic Insulator
• Exciton Mott Transition in Two-Dimensional Semiconductors
• Cluster charge-density-wave glass in hydrogen-intercalated TiSe${}_2$
• Helicoidal excitonic phase in an electron-hole double layer system
• Antiparticle of exciton in semimetals
• Strong long-wavelength electron-phonon coupling in Ta${}_2$Ni(Se,S)${}_5$
• Nodal-antinodal dichotomy from anisotropic quantum critical continua in holographic models
• Optical amplification in a CDW-phase of a quasi-two dimensional material
• Gate tuning of coupled electronic and structural phase transition in atomically thin Ta${}_2$NiSe${}_5$
• Quantum loops in the 1T transition metal dichalcogenides
• Exciton Superfluidity in 2D Heterostructures from First Principles: The importance of material specific screening
• Long-lived Nonlinear Oscillatory States in Interacting Relativistic Bose-Einstein Condensates
• Identifying topological excitonic insulators via bulk-edge correspondence
• Elastic Soft Mode and Electric Quadrupole Response in Excitonic Insulator Candidate (Ta${}_{0.952}$V${}_{0.048}$)${}_2$NiSe${}_5$: Contribution of Electron-Phonon Interaction
• Topological spin-up triplet excitonic condensation in two-dimensional electron-hole systems
• Electromagnetic response in dipole superfluids: vortex lattices and singular domain walls
• Magnetic-field effect on excitonic condensation emergent in extended Falicov-Kimball model
• A monolayer transition metal dichalcogenide as a topological excitonic insulator
• An Exactly Solvable Model of Randomly Pinned Charge Density Waves in Two Dimensions
• Doping-induced nematic and stripe orders within the charge density wave state of TiSe${}_2$
• Interplay of Quantum and Thermal Fluctuations in Two-Dimensional Randomly Pinned Charge Density Waves
• Interplay of Rashba spin-orbit coupling and Coulomb interaction in topological spin-triplet excitonic condensates
• Emergent quantum phenomena in two-dimensional 1T-TaS2
• Raman spectroscopy of van der Waals topological magnet GdGaI
• Long-lived relaxation channel and exciton-phonon coupling in Ta2NiSe5 via non-degenerate pump-probe spectroscopy
• Electronic Coherence Evolution at the Nearly Commensurate Incommensurate CDW Boundary of 1T-TaS2
• Phase Coherent Oscillations of Excitonic Photocapacitance and Bose-Einstein Condensation in Quantum Coupled 0D-2D Heterostructure
• Spin-orbit-driven quarter semimetals in rhombohedral graphene
• Stabilization of sliding ferroelectricity through exciton condensation
• Excitons and Optical Response in Excitonic Insulator Candidate TiSe${}_2$
• Translation-Invariant Excitons in a Phonon Field
• Metal-to-insulator transition in Pt-doped TiSe${}_2$ driven by emergent network of narrow transport channels
• Dynamical signatures and control of time-reversal breaking in twisted nodal superconductors
• Emergence of a condensate with finite-energy Cooper pairing in hybrid exciton/superconductor systems
• Spin-polarized triplet excitonic insulators in Ta3X8 (X=I, Br) monolayers
• Direct evidence for two-gap superconductivity in hydrogen-intercalated titanium diselenide
• Anomalous drag in electron-hole condensates with granulated order
• Revisiting the charge-density-wave superlattice of 1$T$-TiSe${}_2$
• Why a Bose-Einstein condensate cannot exist in a system of interacting bosons at ultrahigh temperatures