Effects of the Interlayer Interaction and Electric Field on the Band Gap of Polar Bilayers: A Case Study of Sc2CO2

Abstract

The two-dimensional Sc2CO2 monolayer has net dipole moments as compared with other functional transition metal carbides. This unique feature may provide potential routes to tune its electronic properties. Herein, the band gap engineering of Sc2CO2 bilayers is investigated by the density functional calculation. We found that the band gap of Sc2CO2 bilayers is not only dependent on the relative stacking position and distance but also on the magnitude and direction of external electric field. The competition between the interlayer van der Waals and electrostatic interactions has been revealed as the dominant mechanism for the band gap modulation of polar bilayers. This works demonstrate that polar bilayers exhibit richer electronic properties than the nonpolar one. The interlayer electric field may be utilized to fabricate novel electronic and optoelectronic devices.