The Combined Effects of an External Field and Novel Functional Groups on the Structural and Electronic Properties of TMDs/TiC Heterostructures: A First-Principles Study.

The stacking of TiC with transition metal dihalide (TMDs) materials is an effective strategy to improve the physical properties of a single material, and the tuning of the related properties of these TMDs/TiC heterostructures is also an important scientific problem. In this work, we systematically investigated the effects of an external field and novel functional groups (S, Se, Cl, Br) on the structural and electronic properties of TMDs/TiCX heterostructures. The results revealed that the lattice parameters and interlayer distance of TMDs/TiC increased with the addition of functional groups. Both tensile and compressive strain obviously increased the interlayer distance of MoS/TiCX (X = S, Se, Cl, Br) and MoSe/TiCX (X = Se, Br). In contrast, the interlayer distance of MoSe/TiCX (X = S, Cl) decreased with increasing compressive strain. Furthermore, the conductivity of TMDs/TiC increased due to the addition of functional groups (Cl, Br). Strain caused the bandgap of TMDs to narrow, and effectively adjusted the electronic properties of TMDs/TiCX. At 9% compressive strain, the conductivity of MoSe/TiCCl increased significantly. Meanwhile, for TMDs/TiCX, the conduction band edge (CBE) and valence band edge (VBE) at the M and K points changed linearly under an electric field. This study provides valuable insight into the combined effects of an external field and novel functional groups on the related properties of TMDs/TiCX.