Multiferroic materials offer a promising avenue for manipulating digital information by leveraging the cross-coupling between ferroelectric and ferromagnetic orders. Despite the ferroelectricity has been uncovered by ion displacement or interlayer-sliding, one-unit-cell of multiferroic materials design and wafer-scale synthesis have yet to be realized. Here we develope an interface modulated strategy to grow 1-inch one-unit-cell of non-layered chromium sulfide with unidirectional orientation on industry-compatible c-plane sapphire. The interfacial interaction between chromium sulfide and substrate induces the intralayer-sliding of self-intercalated chromium atoms and breaks the space reversal symmetry. As a result, robust room-temperature ferroelectricity (retaining more than one month) emerges in one-unit-cell of chromium sulfide with ultrahigh remanent polarization. Besides, long-range ferromagnetic order is discovered with the Curie temperature approaching 200 K, almost two times higher than that of bulk counterpart. In parallel, the magnetoelectric coupling is certified and which makes 1-inch one-unit-cell of chromium sulfide the largest and thinnest multiferroics.

多铁材料通过利用铁电和铁磁序之间的交叉耦合，为操纵数字信息提供了一种有前途的途径。尽管通过离子位移或层间滑动揭示了铁电性，但多铁材料的单晶胞设计和晶圆级合成尚未实现。在这里，我们开发了一种界面调制策略，在工业兼容的c面蓝宝石上生长单向取向的 1 英寸单晶非层状硫化铬。硫化铬与基底之间的界面相互作用引起自插层铬原子的层内滑动并打破了空间反转对称性。结果，硫化铬单晶电池中出现了强大的室温铁电性（保持超过一个月），并具有超高的剩余极化强度。此外，还发现了长程铁磁有序，其居里温度接近200 K，几乎是块体对应物的两倍。同时，磁电耦合也得到了认证，这使得 1 英寸硫化铬单电池成为最大、最薄的多铁性材料。