Controllable\nSynthesis of High-Quality Magnetic Topological\nInsulator MnBi<sub>2</sub>Te<sub>4</sub> and MnBi<sub>4</sub>Te<sub>7</sub> Multilayers by Chemical Vapor Deposition

With a nontrivial topological band and intrinsic magnetic\norder,\ntwo-dimensional (2D) MnBi<sub>2</sub>Te<sub>4</sub>-family materials\nexhibit great promise for exploring exotic quantum phenomena and\npotential applications. However, the synthesis of 2D MnBi<sub>2</sub>Te<sub>4</sub>-family materials via chemical vapor deposition (CVD),\nwhich is essential for advancing device applications, still remains\na significant challenge since it is difficult to control the reactions\namong multi-precursors and form pure phases. Here, we report a controllable\nsynthesis of high-quality magnetic topological insulator MnBi<sub>2</sub>Te<sub>4</sub> and MnBi<sub>4</sub>Te<sub>7</sub> multilayers\nvia an evaporation-rate-controlled CVD approach. The multilayers are\ngrown on a mica substrate epitaxially, exhibiting a regular triangle\nshape. By controlling growth temperatures, the thickness and lateral\nsize of the 2D MnBi<sub>2</sub>Te<sub>4</sub> are well regulated.\nFurthermore, the magneto-transport measurements clearly reveal multistep\nspin-flop transitions for both odd- and even-number-layered MnBi<sub>2</sub>Te<sub>4</sub> multilayers. Our study marks a significant\nstride toward future transformative applications in devices based\non high-quality, edge- and thickness-controlled 2D magnetic topological\nquantum materials.