Speakers
Description
The structural stability and mechanical properties of Janus monolayer transition metal carbidesulfides MSC (M=Zr, Hf, Ti) in the 1H phase are systematically investigated using first-principles calculations. Cohesive energy calculations reveal that the 1H phase is consistently more stable than the 1T phase across all three compounds, with energy differences ranging from 0.50 to 0.67 eV/atom, thereby rendering the 1T phase energetically unfavorable for further mechanical evaluation. Among the three 1H-phase materials, ZrSC exhibits the highest cohesive energy of -6.985 eV/atom, followed closely by HfSC (-6.912 eV/atom) and TiSC (-6.586 eV/atom). Elastic constant analysis demonstrates that ZrSC possesses the highest in-plane stiffness (C = 207.0 N/m) and bulk modulus (103.5 N/m), indicating superior mechanical robustness. HfSC shows intermediate in-plane stiffness (C = 180.5 N/m) and bulk modulus (90.3 N/m), while TiSC exhibits the lowest values for both properties (C = 164.6 N/m, K = 82.3 N/m). Furthermore, HfSC and TiSC show significantly lower C₄₄ values (21.1 and 20.6 N/m, respectively) and high Poisson’s ratios (0.621 and 0.600), suggesting substantial mechanical anisotropy and enhanced flexibility compared to ZrSC. The Young’s moduli of all three compounds range from 65.9 to 70.7 N/m, indicating moderate but comparable tensile stiffness. These findings establish ZrSC 1H as the most mechanically stiff and energetically stable candidate among the series, while HfSC and TiSC 1H phases offer greater ductility, making them potentially suitable for flexible electronic applications.