Strong Coupling Nature of the Excitonic Insulator State in Ta2NiSe5

Koudai Sugimoto, Satoshi Nishimoto, Tatsuya Kaneko, Yukinori Ohta

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We analyze the measured optical conductivity spectra using the density-functional-theory-based electronic structure calculation and density-matrix renormalization group calculation of an effective model. We show that, in contrast to a conventional description, the Bose-Einstein condensation of preformed excitons occurs in Ta2NiSe5, despite the fact that a noninteracting band structure is a band-overlap semimetal rather than a small band-gap semiconductor. The system above the transition temperature is therefore not a semimetal but rather a state of preformed excitons with a finite band gap. A novel insulator state caused by the strong electron-hole attraction is thus established in a real material.

Original languageEnglish
Article number247602
JournalPhysical Review Letters
Volume120
Issue number24
DOIs
Publication statusPublished - 2018 Jun 14
Externally publishedYes

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insulators
metalloids
excitons
attraction
condensation
transition temperature
density functional theory
electronic structure
conductivity

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Strong Coupling Nature of the Excitonic Insulator State in Ta2NiSe5. / Sugimoto, Koudai; Nishimoto, Satoshi; Kaneko, Tatsuya; Ohta, Yukinori.

In: Physical Review Letters, Vol. 120, No. 24, 247602, 14.06.2018.

Research output: Contribution to journalArticle

Sugimoto, Koudai ; Nishimoto, Satoshi ; Kaneko, Tatsuya ; Ohta, Yukinori. / Strong Coupling Nature of the Excitonic Insulator State in Ta2NiSe5. In: Physical Review Letters. 2018 ; Vol. 120, No. 24.
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