Fig. 1

Top and side views of the β-phase MX2N4 (M = Mo, W; X = Si, Ge) monolayers. The solid red and blue dotted lines represent the hexagonal protocellular lattices defined by a and b and the orthogonal supercell defined by x and y, respectively.

Top and side views of the β-phase MX2N4 (M = Mo, W; X = Si, Ge) monolayers. The solid red and blue dotted lines represent the hexagonal protocellular lattices defined by a and b and the orthogonal supercell defined by x and y, respectively.