Interaction-induced merging of Dirac points in non-Abelian optical lattices

Li Wang and Libin Fu
Phys. Rev. A 87, 053612 – Published 20 May 2013

Abstract

We study the properties of an ultracold Fermi gas loaded in a square optical lattice and subjected to an external and classical non-Abelian gauge field. We calculate the energy spectrum of the system and show that the Dirac points in the energy spectrum will remain quite stable under on-site interaction of certain strength. Once the on-site interaction grows stronger than a critical value, the Dirac points will no longer be stable and merge into a single hybrid point. This merging implies a quantum phase transition from a semimetallic phase to a band insulator. The on-site interaction between ultracold fermions could be conveniently controlled by Feshbach resonances in current experiments. We propose that this interaction-induced merging of Dirac points may be observed in the ultracold-Fermi-gas experiments.

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  • Received 3 September 2012

DOI:https://doi.org/10.1103/PhysRevA.87.053612

©2013 American Physical Society

Authors & Affiliations

Li Wang1 and Libin Fu1,2,*

  • 1National Laboratory of Science and Technology on Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
  • 2HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100084, China

  • *lbfu@iapcm.ac.cn

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Vol. 87, Iss. 5 — May 2013

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