Strain Effects On Quantum Anomalous Hall Effect In Graphene

In this paper, we investigate the effect of stains on Quantum anomalous Hall effect ingraphene by the tight-banding model and the calculation of Berry curvature.Ever since its discovery the notion of Berry phase has permeated through all branchesof physics.Researchers have gradually realized that the Berry phase of the eletronic wavefunction can have a profound effect on material properties and is responsible for a spectrum ofphenomena,such as polarization,orbital magnetism,various (quantum,anomalous or spin) Halleffect, and quantum charge pumping.The integral of Berry phase of a field is known to beBerry curvature which is an essential ingredient to our understanding of basic materialproperties.We demonstrated the concept of strain-induced band-structure engineering in graphenethrough the calculation of its electronic properties under uniaxial(armchair or zigzag direction)and shear deformations.Interestingly enough, the use of strain (strain of zigzag direction orshear strain) allows for a gap opening at moderate absolute deformation and the gap can betuned by varying the strain parameters. The Dirac cones not only moved,but also mergesultimatly when the strain increase to a moderate value.We investigate the possibility of realizing quantum anomalous Hall effect in graphene inthe presence of strain.Reachers have already point out a practical way to induce a quantizedHall conductivity in graphene via both Rashba spin-orbit coupling and an exchangefield.Berry curvature and a nonzero Chern number should be observable in the presence ofRashba spin-orbit coupling and an exchange field.But when the strain (armchair and zigzagdirection or shear deformations) is applied,We calculated the Berry curvature distribution andfound that the strain should change the Berry curvature and a nonzero Chern is no longerexist.The larger the deformation is,more obviously the change of Berry curvature will be.Thus we found the strain should broken Quantum anomalous Hall effect as a conclusion.