Excitonic order and superconductivity in the two-orbital hubbard model: Variational cluster approach

Ryo Fujiuchi, Koudai Sugimoto, Yukinori Ohta

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3 Citations (Scopus)

Abstract

Using the variational cluster approach based on the self-energy functional theory, we study the possible occurrence of excitonic order and superconductivity in the two-orbital Hubbard model with intra- and inter-orbital Coulomb interactions. It is known that an antiferromagnetic Mott insulator state appears in the regime of strong intra-orbital interaction, a band insulator state appears in the regime of strong inter-orbital interaction, and an excitonic insulator state appears between them. In addition to these states, we find that the s±-wave superconducting state appears in the small-correlation regime, and the dx2y2-wave superconducting state appears on the boundary of the antiferromagnetic Mott insulator state. We calculate the single-particle spectral function of the model and compare the band gap formation due to the superconducting and excitonic orders.

Original languageEnglish
Article number063705-1
JournalJournal of the Physical Society of Japan
Volume87
Issue number6
DOIs
Publication statusPublished - 2018

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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