Transition metal tin-chalcogenides (TMTC): a new class of 2D covalent metals with high conductivity and stability for advanced applications

Abstract The successful synthesis of transition metal carbon-chalcogenides (TMCCs) has marked a significant breakthrough in the study of two-dimensional (2D) metals. However, the chemical diversity of this family remains limited to transition metal elements and carbon-based structures. In this study, we explore the potential to expand this family by replacing carbon with tin, leading to the discovery of a novel class of materials: transition metal tin-chalcogenides (TMTCs). Using density functional theory (DFT) calculations, we identified nine stable TMTC structures exhibiting both dynamical and thermal stability. Notably, these materials display metallic behavior, with a finite density of states at the Fermi level, suggesting high electrical conductivity and highlighting their potential for applications in electronics and energy storage systems. Among the nine TMTC compounds, two (Nb 2 S 2 Sn and Ta 2 S 2 Sn) exhibit predominantly ionic bonding, whereas the remaining seven (Cr 2 S 2 Sn, Fe 2 S 2 Sn, Mn 2 S 2 Sn, Mo 2 S 2 Sn, Re 2 S 2 Sn, Tc 2 S 2 Sn, and W 2 S 2 Sn) are characterized as 2D covalent metals. The TMTC family presents an opportunity to enhance the functional properties of widely studied transition metal dichalcogenides (TMDs), with potential applications in nanoelectronics, nanophotonics, biomedicine, and energy storage.