Photo-induced enhancement of excitonic order

Abstract

We study the dynamics of excitonic insulators coupled to phonons. Without phonon couplings, the linear response is given by the damped amplitude oscillations of the order parameter with frequency equal to the minimum band gap. A phonon coupling to the interband transfer integral induces two types of long-lived collective oscillations of the amplitude, one originating from the phonon dynamics and the other from the phase mode, which becomes massive. We show that even for small phonon coupling, a photo-induced enhancement of the exciton condensation and the gap can be realized. Using the Anderson pseudo-spin picture, we argue that the origin of the enhancement is a cooperative effect of the massive phase mode and the Hartree shift induced by the photo excitation. We also discuss how the enhancement of the order and the collective modes can be observed with time-resolved photo-emission spectroscopy.

5pages, 4 figures + 8 pages, 8 figures

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Cited by in corpus (23)

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• Charge-density-wave melting in the one-dimensional Holstein model
• Second order Josephson effect in excitonic insulators
• Lattice dynamics of the excitonic insulator Ta${}_2$Ni(Se${}_{1-x}$S${}_x$)${}_5$
• Role of electron-phonon coupling in excitonic insulator candidate Ta2NiSe5
• Effect of Cu intercalation and pressure on excitonic interaction in 1T-TiSe2
• 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
• Photoinduced metallization of excitonic insulators
• Third-harmonic generation in excitonic insulators
• Photo-induced Dirac cone flattening in BaNiS${}_2$
• Collective modes and Raman response in Ta${}_2$NiSe${}_5$
• Orbitally Selective Resonant Photodoping to Enhance Superconductivity
• Excitonic ordering in strongly correlated spin crossover systems: induced magnetism and excitonic excitation spectrum
• Strong enhancement of magnetic susceptibility induced by spin-nematic fluctuations in an excitonic insulating system with spin-orbit coupling
• Theory of Thermal Conductivity on Excitonic Insulator
• Photo-induced Dynamics of Quasicrystalline Excitonic Insulator
• Photoinduced dynamics of excitonic order and Rabi oscillation in the two-orbital Hubbard model
• Mechanism for Synchronization of Charge Oscillations in Dimer Lattices
• Long-lived relaxation channel and exciton-phonon coupling in Ta2NiSe5 via non-degenerate pump-probe spectroscopy
• Probing the collective excitations of excitonic insulators in an optical cavity