Excitonic Bose-Einstein condensation in Ta2NiSe5 above room temperature

Abstract

We show that finite temperature variational cluster approximation (VCA) calculations on an extended Falicov-Kimball model can reproduce angle-resolved photoemission spectroscopy (ARPES) results on Ta2NiSe5 across a semiconductor-to-semiconductor structural phase transition at 325 K. We demonstrate that the characteristic temperature dependence of the flat-top valence band observed by ARPES is reproduced by the VCA calculation on the realistic model for an excitonic insulator only when the strong excitonic fluctuation is taken into account. The present calculations indicate that Ta2NiSe5 falls in the Bose-Einstein condensation regime of the excitonic insulator state.

21 pages(5 figures)

References in corpus (6)

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• Self-energy-functional approach: Analytical results and the Mott-Hubbard transition
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Cited by in corpus (22)

• Photo-induced enhancement of excitonic order
• Charge-density wave induced by combined electron-electron and electron-phonon interactions in 1$T$-TiSe${}_2$: A variational Monte Carlo study
• Hybridization-gap Formation and Superconductivity in the Pressure-induced Semimetallic Phase of the Excitonic Insulator Ta${}_2$NiSe${}_5$
• Signatures of ultrafast reversal of excitonic order in Ta${}_2$NiSe${}_5$
• Anomalous excitonic phase diagram in band-gap-tuned Ta2Ni(Se,S)5
• Orbital diamagnetic susceptibility in excitonic condensation phase
• Electric and magnetic multipoles and bond orders in excitonic insulators
• Low-energy excitation spectra in the excitonic phase of cobalt oxides
• 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
• Evolution of the electronic structure in Ta${}_2$NiSe${}_5$ across the structural transition revealed by resonant inelastic x-ray scattering
• Ta2NiSe5: a candidate topological excitonic insulator with multiple band inversions
• Finite-temperature photoemission in the extended Falicov-Kimball model: a case study for Ta${}_2$NiSe${}_5$
• Excitonic Insulator State of the Extended Falicov-Kimball Model in the Cluster Dynamical Impurity Approximation
• In-plane magnetic field induced density wave states near quantum spin Hall phase transitions
• Theory of Orbital Susceptibility on Excitonic Insulator
• Perturbation of charge density waves in 1T-TiSe${}_2$
• Transition to an excitonic insulator from a two-dimensional conventional insulator
• Photoinduced dynamics of excitonic order and Rabi oscillation in the two-orbital Hubbard model
• Detecting photoelectrons from spontaneously formed excitons
• 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
• Comment on "Direct observation of excitonic instability in Ta${}_2$NiSe${}_5$" [arXiv:2007.08212 (2020)]