  Two-dimensional (2D) multiferroics exhibit cross-control capacity between
magnetic and electric responses in reduced spatial domain, making them well
suited for next-generation nanoscale devices; however, progress has been slow
in developing materials with required characteristic properties. Here we
identify by first-principles calculations robust 2D multiferroic behaviors in
decorated Fe2O3 monolayer, showcasing N@Fe2O3 as a prototypical case, where
ferroelectricity and ferromagnetism stem from the same origin, namely Fe
d-orbit splitting induced by the Jahn-Teller distortion and associated crystal
field changes. The resulting ferromagnetic and ferroelectric polarization can
be effectively reversed and regulated by applied electric field or strain,
offering efficient functionality. These findings establish strong materials
phenomena and elucidate underlying physics mechanism in a family of truly 2D
multiferroics that are highly promising for advanced device applications.
