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Dynamical mean field theory equations on nearly real frequency axis

Fathi, M. B ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.physb.2009.12.063
  3. Abstract:
  4. The iterated perturbation theory (IPT) equations of the dynamical mean field theory (DMFT) for the half-filled Hubbard model are solved on nearly real frequencies at various values of the Hubbard parameters, U, to investigate the nature of metal-insulator transition (MIT) at finite temperatures. This method avoids the instabilities associated with the infamous Padé analytic continuation and reveals fine structures across the MIT at finite temperatures, which cannot be captured by conventional methods for solving DMFT-IPT equations on Matsubara frequencies. Our method suggests that at finite temperatures, there is a crossover from a bad metal to a bad insulator in which the height of the quasi-particle (Kondo) peak decreases to a non-zero small bump, which gradually suppresses as one moves deeper into the bad insulating regime
  5. Keywords:
  6. Diagrammatic ; DMFT ; IPT ; Analytic continuation ; Analytical continuation ; Bad metals ; Conventional methods ; Dynamical mean-field theory ; Fine structures ; Finite temperatures ; Frequency axis ; Hubbard ; Matsubara frequency ; Perturbation theory ; Quasi particles ; Insulation ; Mean field theory ; Metal insulator boundaries ; Perturbation techniques ; Semiconductor insulator boundaries ; Statistical mechanics ; Metal insulator transition
  7. Source: Physica B: Condensed Matter ; Volume 405, Issue 6 , 2010 , Pages 1658-1661 ; 09214526 (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S0921452609015452