Germanene nanomeshes: Cooperative effects of degenerate perturbation and uniaxial strain on tuning bandgap

• 来源期刊: 中国物理B（英文版）
• 关键词: first-principles calculation novel two-dimensional nanostructure bandgap engineering
• 年，卷（期）: 2017,（10）
• 页码范围: 446-452
• 页数: 7页
• 语种: 英文
• DOI: 10.1088/1674-1056/26/10/108101

摘要

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 and πz bands with energy interval Estrain to shift the Dirac cone.Also,the inversion symmetry preserved antidot can split πa (πz) into πa1 and πa2 (rzl and πz2) bands with energy interval Edefect to open bandgap in the nanomesh withΓ as four-fold degenerate Dirac point according to the band-folding analysis.Though the Edefect 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.