Van der Waals heterostructures of MoS2 and Janus MoSSe monolayers on graphitic boron-carbon-nitride (BC3, C3N, C3N4 and C4N3) nanosheets: a first-principles study

In this work, we extensively investigate the structural and electronic properties of van der Waals heterostructures (HTs) constructed by MoS2/BC3, MoS2/C3N, MoS2/C3N4, MoS2/C4N3 and those using Janus MoSSe instead of MoS(2)by performing density functional theory calculations. The electronic band structure calculations and the corresponding partial density of states reveal that the significant changes are driven by a quite strong layer-layer interaction between the constitutive layers. Our results show that although all monolayers are semiconductors as free-standing layers, the MoS2/C3N and MoS2/C4N3 bilayer HTs display metallic behavior as a consequence of the transfer of charge carriers between two constituent layers. In addition, it is found that in the MoSSe/C3N bilayer HT, the degree of metallicity is affected by the interface chalcogen atom type when Se atoms face the C3N layer, and the overlap of the bands around the Fermi level is smaller. Moreover, the half-metallic magnetic C4N3 is shown to form a magnetic half-metallic trilayer HT with MoS(2)independent of the stacking sequence, i.e. whether it is sandwiched or a two C4N3 layer encapsulate MoS2 layer. We further analyze the trilayer HTs in which MoS2 is encapsulated by two different monolayers and it is revealed that at least with one magnetic monolayer, it is possible to construct a magnetic trilayer. While the trilayer of C4N3/MoS2/BC3 and C4N3/MoS2/C3N4 exhibit half-metallic characteristics, C4N3/MoS2/C3N possesses a magnetic metallic ground state. Overall, our results reveal that holly structures of BCN crystals are suitable for heterostructure formation even over a van der Waals-type interaction, which significantly changes the electronic nature of the constituent layers.