Influence of different exchange-correlation potentials on twisted structures of bilayer XS2 (X= Mo, Cr)

Abstract

In this work, we employ the LDA, GGA and GGA with four vdW corrections to study crystal and electronic structures of bilayer transition metal dichalcogenides (TMDs) with different twist angles. We find the GGA interlayer distance of bilayer MoS2 has good agreement with experimental value while vdW correction method still needs to be further improved. Our results indicate the GGA interlayer distances of bilayer XS2 (X= Mo, Cr) with twist angles are smaller than that of normal bilayer, which is the opposite in the LDA case. The GGA results show that reduced bandgap is due to the reduction of interlayer distance and, flat valley and conductivity bands appear owing to twist angle. Our study not only supports valuable information for application possibility of twisted two-dimensional (2D) materials but also stimulates more related research.