Phase-dependent electronic and magnetic properties of Ti2C monolayers

Abstract

Achieving tunable magnetism in low-dimensions is an essential step to realize novel spintronic applications. In this manner, two-dimensional transition metal carbides/nitrides (MXenes) with intrinsic magnetism have attracted significant interest. In this study, we extensively examine the structural and magnetic properties of 1T- and 2H-Ti2C monolayers by using first-principles techniques. We reveal the dynamical stability of both phases by using phonon spectra analysis and ab initio molecular dynamics simulations. The magnetic ground state is determined by considering all possible spin configurations and taking into account spin-orbit coupling effects, strong onsite Coulomb interaction, and corrected self-interaction terms. Our results indicate that while 1T-Ti2C is anti-ferromagnetic, 2H-Ti2C exhibits ferromagnetism, which is stable at/above room temperature. The electronic structure analysis demonstrates that 1T-Ti2C is an indirect bandgap semiconductor and 2H-Ti2C is a half-metal with 100% spin-polarization. Additionally, it is shown that the magnetic state is robust against low mechanical deformations and fundamental bandgap (also half-metallic bandgap) can be tuned by compressive/tensile strain. Phase-dependent and tunable electronic and magnetic properties of Ti2C monolayers offer new opportunities in the field of low-dimensional magnetism. Published under license by AIP Publishing.