A first principles-based study of structure-property relationships for two-dimensional transition metal dichalcogenides for next-generation electronic devices

The commercial successes of graphene have attracted global attention in the field of atomically thin materials leading to the discovery of novel classes of two-dimensional (2D) materials, such as transition metal oxides, and transition metal dichalcogenides. The market share of transition metal dichalcogenides (TMDCs) is poised to proliferate in the future; for example, the market cap of MoS 2 is poised to reach $743 billion by 2025. 2D TMDCs (MX 2 ) have a 1:2 ratio of transition metal (M= Mo, W, V, etc.) and chalcogens (X = S, Se, Te). Moreover, multilayers of these systems may also exist as 2H, 1T, 3R, and 4T phases depending on the stacking arrangement. Owing to these unique characteristics, these materials are vital for research and commercial applications. Therefore, studying the mechanical properties of 2D TMDCS is essential to harness their potential. 

Moreover, simulations predict that the elastic constants of 2D MoS2 depend on its structural phase, owing to a difference in their cohesive energies. Additionally, both the in-plane stiffness and strength of MoS2 can deteriorate in the presence of crystallographic defects [8]. Furthermore, chemistry can also play a significant role as theoretical calculations predict that the stiffness of MoS 2 functionalized with H-atoms can increase at the cost of UTS and stretchability. However, if such structure-property relationships are valid for other 2D TMDCs is not clear.

Our recent first-principles studies on 2D vanadium dichalcogenides (VX₂, X=S, Se) have uncovered unique spin-lattice-transport phenomena. In monolayer VS₂, we demonstrated a dramatic 4x drop in lattice thermal conductivity at the ferromagnetic–paramagnetic transition (Nanoscale (2025, 17, 6550)), due to spin-dependent anharmonic stiffening of V–S bonds and enhanced phonon–magnon scattering. To assess mechanical robustness, we compute phonon spectra under applied strain: the onset of imaginary modes signals the ideal strength limit, as in other 2D crystals. We further started investigating thermoelectric performance using advanced many-body transport simulations. By combining GW quasiparticle corrections with ab initio electron–phonon scattering (via EPW and Perturbo codes, we are trying to obtain parameter-free carrier lifetimes and mobilities. This integrated approach yields predictive Seebeck coefficients and electrical conductivities for these magnetic 2D materials. The combination of spin-controlled thermal transport, mechanical stability analysis, and first-principles transport modeling is highly novel and can guide the design of 2D energy materials for efficient waste-heat-to-electricity conversion and spin-caloritronic devices.