Tunable indirect to direct band gap transition of monolayer Sc₂CO₂ by the strain effect.

MXene has not yet been investigated in optical applications because it is a newly suggested two-dimensional material. In the present work, the first investigation of the prospects of MXene as a novel optical nanodevice was done by applying strain to monolayer Sc2CO2 using first-principles density-functional theory. This single-layer material experiences an indirect to direct band gap transition with variation of the band gap size at a relatively small critical strain of about 2%. The present work emphasizes that monolayer MXene can become a promising material for an optical nanodevice by modulating the band gap properties using strain engineering.