Within the family of two-dimensional dielectrics, rhombohedral boron nitride (rBN) is considerably promising owing to having not only the superior properties of hexagonal boron nitride^1,2,3,4—including low permittivity and dissipation, strong electrical insulation, good chemical stability, high thermal conductivity and atomic flatness without dangling bonds—but also useful optical nonlinearity and interfacial ferroelectricity originating from the broken in-plane and out-of-plane centrosymmetry^{5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23}. However, the preparation of large-sized single-crystal rBN layers remains a challenge^24,25,26, owing to the requisite unprecedented growth controls to coordinate the lattice orientation of each layer and the sliding vector of every interface. Here we report a facile methodology using bevel-edge epitaxy to prepare centimetre-sized single-crystal rBN layers with exact interlayer ABC stacking on a vicinal nickel surface. We realized successful accurate fabrication over a single-crystal nickel substrate with bunched step edges of the terrace facet (100) at the bevel facet (110), which simultaneously guided the consistent boron–nitrogen bond orientation in each BN layer and the rhombohedral stacking of BN layers via nucleation near each bevel facet. The pure rhombohedral phase of the as-grown BN layers was verified, and consequently showed robust, homogeneous and switchable ferroelectricity with a high Curie temperature. Our work provides an effective route for accurate stacking-controlled growth of single-crystal two-dimensional layers and presents a foundation for applicable multifunctional devices based on stacked two-dimensional materials.

在二维电介质家族中，菱形氮化硼 (rBN) 具有相当大的前景，因为它不仅具有六方氮化硼^1,2,3,4的优异性能，包括低介电常数和耗散、强电绝缘性、良好的化学性能稳定性、高热导率和原子平坦度，无悬空键，而且还具有有用的光学非线性和界面铁电性，这些特性源自面内和面外中心对称性的破坏^{5,6,7,8,9,10,11,12, 13,14,15,16,17,18,19,20,21,22,23}。然而，由于需要前所未有的生长控制来协调每层的晶格取向和每个界面的滑动矢量，大尺寸单晶 rBN 层的制备仍然是一个挑战^24,25,26 。在这里，我们报告了一种简单的方法，使用斜边外延来制备厘米大小的单晶 rBN 层，并在邻位镍表面上具有精确的层间 ABC 堆叠。我们在斜面（110）处成功地精确制造了平台面（100）的阶梯边缘的单晶镍基板，同时引导了每个 BN 层中一致的硼氮键方向和菱面体堆叠。 BN 通过每个斜面附近的成核形成层。所生长的 BN 层的纯菱面体相得到了验证，因此表现出鲁棒、均匀、可切换的铁电性和高居里温度。我们的工作为单晶二维层的精确堆叠控制生长提供了有效途径，并为基于堆叠二维材料的适用多功能器件奠定了基础。