Nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators

Tetsuhiro Tanabe, Koudai Sugimoto, Yukinori Ohta

Research output: Contribution to journalArticle

1 Citation (Scopus)

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.

Original languageEnglish
Article number235127
JournalPhysical Review B
Volume98
Issue number23
DOIs
Publication statusPublished - 2018 Dec 12
Externally publishedYes

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insulators
Pumps
Spectroscopy
pumps
probes
Energy gap
pulses
Bose-Einstein condensation
spectroscopy
Optical conductivity
Hamiltonians
Band structure
pumping
condensation
degrees of freedom
orbitals
conductivity
approximation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators. / Tanabe, Tetsuhiro; Sugimoto, Koudai; Ohta, Yukinori.

In: Physical Review B, Vol. 98, No. 23, 235127, 12.12.2018.

Research output: Contribution to journalArticle

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