AI 中文总结
研究解决菱面体石墨烯多层膜外延制备受限问题，通过4°偏轴4H-SiC的一步石墨化路线，实现厚度可调的菱面体石墨烯平带态制备，确立了相关外延平台。
AI 中文摘要
菱面体石墨烯多层膜为关联拓扑平带物理提供了无莫尔条纹的平台，但直接、无转移的厚度可调多层膜外延制备仍受限。本文报道了在4°偏轴4H-SiC上的一步石墨化路线，其中高温快速退火同时驱动自组织台阶聚集和多层石墨烯形成。原子分辨截面扫描透射电子显微镜识别出局域ABC堆垛，并区分菱面体堆垛与Bernal堆垛；通过改变单一参数（退火温度），厚度可从双层调至20层以上。角分辨光电子能谱直接追踪了厚度依赖的演化：从界面主导的低能态向厚多层膜中显著的近费米能级平带谱权重转变。对17层薄膜的低温扫描隧道显微镜与扫描隧道谱进一步揭示了13.4 meV的低能谱重构和√3×√3的类Kekulé调制，提供了与谷间混合电子结构一致的微观特征。这种一步、无转移方法确立了台阶聚集SiC作为连接堆垛工程与无莫尔条纹关联平带电子态的外延平台。
英文摘要
Rhombohedral graphene multilayers provide a moiré-free platform for correlated and topological flat-band physics, but direct, transfer-free epitaxial access to thickness-tunable multilayers remains limited. Here we report a one-step graphitization route on 4$^\circ$ off-axis 4H-SiC, in which high-temperature flash annealing simultaneously drives self-organized step bunching and multilayer graphene formation. Atomic-resolution cross-sectional scanning transmission electron microscopy identify local ABC registry and distinguish rhombohedral from Bernal stacking. The thickness is tuned from bilayer to more than twenty layers by varying single parameter, the annealing temperature. Angle-resolved photoemission spectroscopy directly tracks the thickness-dependent evolution from interface-dominated low-energy states toward pronounced near-Fermi-level flat-band spectral weight in thick multilayers. Low-temperature scanning tunneling microscopy and spectroscopy on a 17-layer film further reveal a 13.4 meV low-energy spectral reconstruction and a $\sqrt{3} \times \sqrt{3}$ Kekulé-like modulation, providing microscopic signatures consistent with an intervalley-mixed electronic texture. This one-step, transfer-free approach establishes step-bunched SiC as an epitaxial platform that links stacking engineering with moiré-free correlated flat-band electronic states.
