Nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators

Abstract

We study the nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators using the spinless two-orbital model with phonon degrees of freedom in the time-dependent mean-field approximation. We introduce the pulse light as a time-dependent vector potential via the Peierls phase in the Hamiltonian. We find that, in the Bose-Einstein condensation regime where the normal state is semiconducting, the excitonic order is suppressed when the frequency of the pulse light is slightly larger than the band gap, while the order is enhanced when the frequency of the pulse is much larger than the band gap. We moreover find that the excitonic order is completely destroyed in the former situation if the intensity of the pulse is sufficiently strong. In the BCS regime where the normal state is semimetallic, we find that the excitonic order is always suppressed, irrespective of the frequency of the pulse light. The quasiparticle band structure and optical conductivity spectrum after the pumping are also calculated for the instantaneous states.

8 pages, 7 figures, to appear in Physical Review B

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Cited by in corpus (21)

• Non-Coulomb strong electron-hole binding in $T{a}_{2}NiS{e}_5$ revealed by time- and angle-resolved photoemission spectroscopy
• Detecting electron-phonon couplings during photo-induced phase transition
• Ultrafast melting and recovery of collective order in the excitonic insulator Ta${}_2$NiSe${}_5$
• Comparing the generalized Kadanoff-Baym ansatz with the full Kadanoff-Baym equations for an excitonic insulator out of equilibrium
• Pump driven normal-to-excitonic insulator transition: Josephson oscillations and signatures of BEC-BCS crossover in time-resolved ARPES
• Ultrafast nonequilibrium evolution of excitonic modes in semiconductors
• Photo-induced phase transition and associated time scales in the excitonic insulator Ta${}_2$NiSe${}_5$
• Nonlinear spectroscopy of collective modes in excitonic insulator
• A New Era of Excitonic Insulators
• Unveiling the underlying interactions in Ta2NiSe5 from photo-induced lifetime change
• Signatures of ultrafast reversal of excitonic order in Ta${}_2$NiSe${}_5$
• Photoinduced electron-electron pairing in the extended Falicov-Kimball model
• Nonthermal excitonic condensation near a spin-state transition
• Photoinduced metallization of excitonic insulators
• Effects of Disorder on the Transport of Collective Modes in an Excitonic Condensate
• Third-harmonic generation in excitonic insulators
• Excitonic insulator phase and dynamics of condensate in a topological one-dimensional model
• Photo-induced Dirac cone flattening in BaNiS${}_2$
• Photoinduced dynamics of excitonic order and Rabi oscillation in the two-orbital Hubbard model
• Photo-induced Dynamics of Quasicrystalline Excitonic Insulator
• Optical amplification in a CDW-phase of a quasi-two dimensional material