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
μB). 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 spintronic 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.