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  • High Curie temperature and ...
    Hu, Y; Liu, X. Y; Shen, Z. H; Luo, Z. F; Chen, Z. G; Fan, X. L

    Nanoscale, 06/2020, Letnik: 12, Številka: 21
    Journal Article

    Two-dimensional (2D) magnets with room temperature ferromagnetism and semiconductors with moderate band gap and high carrier mobility are highly desired for applications in nanoscale electronics and spintronics. By performing the first-principles calculations, we investigate novel Fe, Co, Ni carbide based pristine (M 2 C) and functionalized (M 2 CT 2 , T: F, O, OH) MXenes. Our calculations show that Fe 2 C, Co 2 C, Ni 2 C, Fe 2 CF 2 , Fe 2 CO 2 , Fe 2 C(OH) 2 , Co 2 CF 2 , Co 2 C(OH) 2 and Ni 2 CF 2 are dynamically and mechanically stable. More importantly, Fe 2 C, Co 2 C, Fe 2 CF 2 and Fe 2 C(OH) 2 exhibit intrinsic ferromagnetism (magnetic moments 2-5 μ B per unit cell). Monte Carlo simulations suggest high Curie temperatures of 590 and 920 K for Fe 2 C and Fe 2 CF 2 , respectively, at the HSE06 level owing to the large spin magnetic moments and strong ferromagnetic coupling. Based on the deformation potential theory, we predict high and anisotropic hole mobility (0.2-1.4 × 10 4 cm 2 V −1 s −1 ) for semiconducting Fe 2 CO 2 and Co 2 C(OH) 2 . Additionally, Ni 2 CF 2 demonstrates highly anisotropic electron mobility together with a direct band gap. Our results further show the effectiveness of surface functionalization in modulating the electronic and magnetic properties and broadening the properties of MXenes to achieve long-range intrinsic ferromagnetism well above room temperature and high carrier mobility. MXenes have intrinsic and robust ferromagnetism well above room temperature as well as high and anisotropic carrier mobility.