Recent Advances in Unconventional Ferroelectrics and Multiferroics

Emerging ferroic materials may pave a new way to next‐generation nanoelectronic and spintronic devices due to their interesting physical properties. This work systematically reviews unconventional ferroelectric systems, from Hf‐based and elementary ferroelectrics to stacking ferroelectricity, polar metallicity, fractional quantum ferroelectricity, wurtzite‐type ferroelectricity, and freestanding membranes ferroelectricity. Moreover, multiferroic materials are reviewed, particularly the interplay between novel magnetic states and ferroelectricity, as well as ferrovalley‐ferroelectric coupling. Finally, the conclusion is drawn by discussing current challenges and future opportunities in this field.