The structural, electronic, and magnetic properties of substitutional transition metal doping in CrSi2N4 monolayer

After the synthesis of two-dimensional (2D) structures, Mo(W)Si₂N₄ (Hong et al., 2020; Science 369 670), proclaimed the dawn of a new family of 2D materials, including CrSi₂N₄ (CrSiN) semiconductor, which has a band gap of 0.49 eV and boasts remarkable properties. In this regard, we conducted density functional theory to investigate the structural, magnetic, and electronic properties of mono cation doped CrSiN (TM-CrSiN) with substitutional 3d/4d transition metal (TM) (at the Cr site). The bond lengths of TM-N increase as the atomic size of TM increases, and the formation/binding energy can be explained by the atomic size and electronegativity of TM as compared to the corresponding value of Cr. The doped structures with Ti/Zr, V/Nb, Mo, and Mn/Tc are nonmagnetic monolayers. In contrast, the other doped monolayers are magnetic. The doped monolayers with Ti/Zr and Mo are semiconductors with a band gap of 0.20/0.25 eV and 0.52 eV, respectively. It is noteworthy that the structures with Sc/Y, Fe, Co/Rh, Ni/Pd, and Zn/Cd dopants are half-metallic, which makes them suitable monolayers for spintronic applications. We find Cu- and Ag-CrSiN sheets behave as metallic structures and could be utilized in spin-filter devices.