Two-dimensional
(2D) ferroics, including ferromagnets, ferroelectrics,
ferroelastics, and multiferroics, recently have been theoretically
proposed or experimentally revealed. The research has attracted tremendous
attention because of the novel physics and promising applications
for nanoelectronics, revealing ferroics in the 2D limit. In the present
Perspective, we comprehensively review the recent research progress
and also the proposed applications of 2D ferromagnetic, ferroelectric,
and ferroelastic materials from theoretical and experimental viewpoints.
We then introduce the coupling between ferroic orders and highlight
the latest research on 2D multiferroic materials. The promising research
directions and outlooks are discussed at the end of the Perspective.
It is expected that the comprehensive overview of 2D ferroic materials
can provide guidelines for researchers in the area and inspire further
explorations of new physics and ferroic devices.