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Based on the detailed first-principles calculations, we have carefully investigated the defect induced band splitting and its combination with Dirac cone move in bandgap opening. The uniaxial strain can split the π-like bands into πa andπz bands with energy interval Estrain to shift the Dirac cone. Also, the inversion symmetry preserved antidot can split π_a(π_z) into π_(a1) and π_(a2)(π_(z1) and π_(z2)) bands with energy interval E_(defect) to open bandgap in the nanomesh with Γ as four-fold degenerate Dirac point according to the band-folding analysis. Though the E_(defect)would keep almost unaffected, the Estrain would be increased by enhancing the uniaxial strain to continuously tune the gap width. Then the bandgap can be reversibly switched on/off. Our studies of the inversion symmetry preserved nanomesh show distinct difference in bandgap opening mechanism as compared to the one by breaking the sublattice equivalence in the(GaAs)_6 nanoflake patterned nanomesh.Here, the π-band gap remains almost unchanged against strain enhancing.
Based on the detailed first-principles calculations, we have carefully investigated the defect induced band splitting and its combination with Dirac cone move in band gap opening. The uniaxial strain can split the π-like bands into πa and πz bands with energy interval Estrain to shift the Dirac cone. Also, the inversion symmetry preserved antidot can split π_a (π_z) into π_ (a1) and π_ (a2) (π_ (z1) and π_ (z2)) bands with energy interval E_ (defect) to open bandgap in the Though the E_ (defect) would keep almost unaffected, the Estrain would be increased by enhancing the uniaxial strain to continuously tune the gap width. Then the bandgap can be reversibly switched on / off. Our studies of the inversion symmetry preserved nanomesh show distinct difference in band gap opening mechanism as compared to the one by breaking the sublattice equivalence in the (GaAs) _6 nanoflake patterned nanomesh. Here, the π-band gap remains almost unchanged against strain enhancing.