Chirality effect of mechanical and electronic properties of monolayer MoS₂ with vacancies

We present first principles theory calculations about the chirality and vacancy effects of the mechanical and electronic properties of monolayer MoS₂. In the uni-axial tensile tests, chirality effect of the mechanical properties is negligible at zero strain and becomes significant with the increasing strain, regardless of vacancies. The existence of vacancies decreases the Young's modulus and ultimate strength of the MoS₂ structure. During the uni-axial tensile tests, the band gap decreases with the increasing strain, regardless of chirality and vacancies. The band gap is reduced with the intermediate state brought by the existence of vacancies. No chirality effect can be observed on the band gap variations of perfect MoS₂. Chirality effect appears to the band gap variation of defected MoS₂ due to the local lattice relaxation near the vacancies. - Highlights: • Chirality effect can be neglected for band gap variation of perfect MoS₂ lattice. • Chirality effect exists for the band gap variation of the MoS₂ lattice with defect due to the local lattice relaxation. • Existing vacancies reduce both the strength/stiffness and the band gap of MoS₂ lattice