Strain-Spintronics: Modulating Electronic and Magnetic Properties of Hf2MnC2O2 MXene by Uniaxial Strain

Next-generation spintronic nanoscale devices require two-dimensional (2D) materials with robust ferromagnetism. Among 2D materials, MXenes are favorable for spintronic applications due to their high electron conductivity and mobility. A recently reported MXene, Hf2MnC2O2, possesses a high Curie temperature (greater than 800 K) and a high magnetic moment per formula unit (3 mu(B)). Since 2D materials have greater elastic strain limits than their bulk counterparts, their properties can be tuned effectively using strain engineering. Here, we investigate modifications in the structural, electronic, and magnetic properties produced by uniaxial strain on a Hf2MnC2O2 monolayer. The strain-free Hf2MnC2O2 nanosheet is an indirect band-gap semiconductor. Our calculations predict that an indirect-to-direct band-gap transition occurs at about 1-3% tensile strain applied in the armchair direction. At 7% strain applied in the zigzag direction and 9% strain applied in the armchair direction, this semiconductor material becomes a half-metal, which is favorable for applications. Under 4% compressive strain in either direction, a semiconductor-to-metal transition is predicted. More importantly, the Curie temperature of the material can be enhanced significantly by applying tensile strain. For instance, under 8% strain, the Curie temperature becomes greater than 1200 K.