Strong-coupling formula for momentum-dependent susceptibilities in dynamical mean-field theory

Junya Otsuki, Kazuyoshi Yoshimi, Hiroshi Shinaoka, Yusuke Nomura

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Computing momentum-dependent susceptibilities in the dynamical mean-field theory (DMFT) requires solving the Bethe-Salpeter equation, which demands large computational cost. Exploiting the strong-coupling feature of local fluctuations, we derive a simplified formula that can be solved at a considerably lower cost. The validity and the physical meaning of the formula are confirmed by deriving the effective intersite interactions in the strong-coupling limit, such as the kinetic exchange and RKKY interactions. Furthermore, numerical calculations for single-orbital and multiorbital models demonstrate surprisingly wider applicability including a weak-coupling region. Based on this formula, we propose three levels of practical approximations that can be chosen depending on complexity of problems. Simpler evaluations of spin and orbital susceptibilities in multiorbital systems thus become possible within DMFT.

Original languageEnglish
Article number165134
JournalPhysical Review B
Volume99
Issue number16
DOIs
Publication statusPublished - 2019 Apr 23

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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