Optical Response in Excitonic Insulating State: Variational Cluster Approach

Hengyue Li, Junya Otsuki, Makoto Naka, Sumio Ishihara

Research output: Contribution to journalArticlepeer-review

Abstract

Optical responses in an excitonic insulating (EI) system with strong electron correlation are studied. We adopt the two-orbital Hubbard model with a finite energy difference between the two orbitals where the spin state degree of freedom exists. This model is analyzed by the variational cluster approach. In order to include the local electron correlation effect, the vertex correction is taken into account in the formulation of the optical conductivity spectra. We calculate a finite-temperature phase diagram, in which an EI phase appears between a low-spin band insulating state and a high-spin Mott insulating state. Characteristic components of the optical conductivity spectra consisting of a sharp peak and continuum appear in the EI phase. Integrated intensity almost follows the order parameter of the EI state, suggesting that this component is available to identify the EI phases and transitions.

Original languageEnglish
JournalUnknown Journal
Publication statusPublished - 2019 Nov 18

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Optical Response in Excitonic Insulating State: Variational Cluster Approach'. Together they form a unique fingerprint.

Cite this