論文

査読有り
2020年3月

Hubbard model on the honeycomb lattice: From static and dynamical mean-field theories to lattice quantum Monte Carlo simulations

PHYSICAL REVIEW B
  • Marcin Raczkowski
  • ,
  • Robert Peters
  • ,
  • Thi Thu Phung
  • ,
  • Nayuta Takemori
  • ,
  • Fakher F. Assaad
  • ,
  • Andreas Honecker
  • ,
  • Javad Vahedi

101
12
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1103/PhysRevB.101.125103
出版者・発行元
AMER PHYSICAL SOC

We study the one-band Hubbard model on the honeycomb lattice using a combination of quantum Monte Carlo (QMC) simulations and static as well as dynamical mean-field theory (DMFT). This model is known to show a quantum phase transition between a Dirac semimetal and the antiferromagnetic insulator. The aim of this paper is to provide a detailed comparison between these approaches by computing static properties, notably ground-state energy, single-particle gap, double occupancy, and staggered magnetization, as well as dynamical quantities such as the single-particle spectral function. At the static mean-field level, local moments cannot be generated without breaking the SU(2) spin symmetry. The DMFT approximation accounts for temporal fluctuations and thus captures both the evolution of the double occupancy and the resulting local moment formation in the paramagnetic phase. As a consequence, the DMFT approximation is found to be very accurate in the Dirac semimetallic phase where local moment formation is present and the spin correlation length small. However, in the vicinity of the fermion quantum critical point, the spin correlation length diverges and the spontaneous SU(2) symmetry breaking leads to low-lying Goldstone modes in the magnetically ordered phase. The impact of these spin fluctuations on the single-particle spectral function-waterfall features and narrow spin-polaron bands-is only visible in the lattice QMC approach.

Web of Science ® 被引用回数 : 10

リンク情報
DOI
https://doi.org/10.1103/PhysRevB.101.125103
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000518437200004&DestApp=WOS_CPL
ID情報
  • DOI : 10.1103/PhysRevB.101.125103
  • ISSN : 2469-9950
  • eISSN : 2469-9969
  • Web of Science ID : WOS:000518437200004

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