Photoinduced enhancement of excitonic order in the two-orbital Hubbard model

Yasuhiro Tanaka, Manabu Daira, Kenji Yonemitsu

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Photoinduced dynamics in an excitonic insulator is studied theoretically by using a two-orbital Hubbard model on the square lattice where the excitonic phase in the ground state is characterized by the BCS-BEC crossover as a function of the interorbital Coulomb interaction. We consider the case where the order has a wave vector Q=(0,0) and photoexcitation is introduced by a dipole transition. Within the mean-field approximation, we show that the excitonic order can be enhanced by the photoexcitation when the system is initially in the BEC regime of the excitonic phase, whereas it is reduced if the system is initially in the BCS regime. The origin of this difference is discussed from behaviors of momentum distribution functions and momentum-dependent excitonic pair condensation. In particular, we show that the phases of the excitonic pair condensation have an important role in determining whether the excitonic order is enhanced or not.

Original languageEnglish
Article number115105
JournalPhysical Review B
Volume97
Issue number11
DOIs
Publication statusPublished - 2018 Mar 2
Externally publishedYes

Fingerprint

Hubbard model
Photoexcitation
photoexcitation
Condensation
Momentum
condensation
momentum
orbitals
augmentation
Coulomb interactions
Crystal lattices
Ground state
Distribution functions
crossovers
distribution functions
insulators
dipoles
ground state
approximation
interactions

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Photoinduced enhancement of excitonic order in the two-orbital Hubbard model. / Tanaka, Yasuhiro; Daira, Manabu; Yonemitsu, Kenji.

In: Physical Review B, Vol. 97, No. 11, 115105, 02.03.2018.

Research output: Contribution to journalArticle

Tanaka, Yasuhiro ; Daira, Manabu ; Yonemitsu, Kenji. / Photoinduced enhancement of excitonic order in the two-orbital Hubbard model. In: Physical Review B. 2018 ; Vol. 97, No. 11.
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