Monolayer Ti2C MXene: Manipulating Magnetic Property and Electronic Structures by Electric Field

Two-dimensional (2D) layered Ti2C MXene has been synthesized experimentally, and the magnetism of monolayer Ti2C MXene has been predicted theoretically. In this study, based on first-principles calculations, five magnetic configurations of monolayer Ti2C are constructed to predict the magnetic ground state. We find that antiferromagnetic (AFM) state has the lowest energy. By applying an external electric field, monolayer Ti2C changes from an AFM semiconductor to a ferrimagnetic (FIM) semiconductor, half-metal, magnetic metal, nonmagnetic (NM) metal, and NM semiconductor. When the electric field increases beyond a certain value, the magnetic moments of Ti atoms sharply decrease. With the increase of electric field, effective masses decrease significantly, carrier mobility increases and conductivity increases. The magnetic anisotropy energies are calculated and the results show that the out-of-plane direction is magnetic easy axis. Using mean-field approximation method, the Neel temperature of monolayer Ti2C is estimated to be 50K. By applying electric field, the Neel temperature significantly decreases, which shows that the electric field can effectively reduce the high Neel temperature. Therefore, our research suggests that the magnetic and electronic properties of 2D materials can be manipulated by external electric field, which provides a feasible direction for the tuning of nano magnetic devices.