Exploring the Stability and Electronic Properties of Janus TMCSe Monolayers via DFT Calculations

Janus monolayers are two-dimensional materials with distinct chemical compositions on their opposing sides, leading to unique properties and potential applications in various fields. Based on density functional theory (DFT) calculations, we have explored the dynamic stability of a family of Janus monolayers with the general formula TMCSe (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn). Only two explored systems were dynamically and thermal stable: CrCSe and MnCSe, as evidenced by their phonon dispersion curves and molecular dynamics calculations. Their electronic properties and magnetic character have been investigated using their corresponding density of states. The CrCSe monolayer is a 0.4 eV indirect semiconductor, and the magnetic MnCSe monolayer is spin-up metallic and a spin-down semimetal. Electrostatic potential isosurfaces are used to assess the reactivity of the stable monolayers. They indicate that the surfaces of the TMCSe structures are polarized, with the C side exhibiting a strong negative potential and the Se side displaying a more neutral character. This property may lead to applications in many fields, such as Li storage or toxic molecule trapping.