Using the determinant quantum Monte Carlo method,we explore a rich phase diagram featuring strain-induced metal-insulator and magnetic phase transitions in an interacting two-dimensional Dirac fermion system.Asymmetri...Using the determinant quantum Monte Carlo method,we explore a rich phase diagram featuring strain-induced metal-insulator and magnetic phase transitions in an interacting two-dimensional Dirac fermion system.Asymmetric strain applied along the zigzag crystal direction drives the semimetallic regime into a band-insulating phase,or it breaks the antiferromagnetic order of the Mott insulator,inducing a nonmagnetic insulating phase under strong correlations.The critical strain required for band gap opening or for a transport phase transition is significantly reduced in the presence of Coulomb repulsion,while increasing interaction strength makes it more difficult for strain to induce a nonmagnetic phase transition.In addition,we measure in detail the band gap modulation by strain and identify a doping effect whereby doping inhibits band gap opening.Our results provide an effective way to tune the transport gap,which could help extend the applications of graphene,whose zero band gap currently limits its use.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12474218)the Beijing Natural Science Foundation(Grant No.1242022)the Guangxi Key Laboratory of Precision Navigation Technology and Application,Guilin University of Electronic Technology(Grant No.DH202322)。
文摘Using the determinant quantum Monte Carlo method,we explore a rich phase diagram featuring strain-induced metal-insulator and magnetic phase transitions in an interacting two-dimensional Dirac fermion system.Asymmetric strain applied along the zigzag crystal direction drives the semimetallic regime into a band-insulating phase,or it breaks the antiferromagnetic order of the Mott insulator,inducing a nonmagnetic insulating phase under strong correlations.The critical strain required for band gap opening or for a transport phase transition is significantly reduced in the presence of Coulomb repulsion,while increasing interaction strength makes it more difficult for strain to induce a nonmagnetic phase transition.In addition,we measure in detail the band gap modulation by strain and identify a doping effect whereby doping inhibits band gap opening.Our results provide an effective way to tune the transport gap,which could help extend the applications of graphene,whose zero band gap currently limits its use.
