AI 中文总结
本文通过电输运测量发现菱面石墨烯多层膜的相变临界位移场具有特殊层依赖关系，确立层数为调控其关联与拓扑相的关键旋钮，还观测到表面态主导的输运特征。
AI 中文摘要
菱面石墨烯多层膜具有层极化平带，为关联拓扑电子态提供了有趣平台，但层数在调控对称性破缺和表面屏蔽中的作用仍不明确。本文制备菱面石墨烯多层膜并开展系统电输运测量，揭示了非常规的相变层依赖关系：从层反铁磁（LAF）到半金属转变的临界位移场（Dc）在四层到六层石墨烯中保持恒定，而从半金属到层极化绝缘体（LPI）转变的Dc随层数增加而增大，这与未屏蔽库仑相互作用模型不符。在六层石墨烯中，出现表面态主导的输运，朗道能级（LLs）和电阻峰可由相邻栅极选择性调控，这是薄层样品中不存在的强层间屏蔽的特征。高磁场下观测到谷层锁定的朗道能级和可能源于层间背散射的耗散态，证明存在解耦的表面态。本研究确立了层数作为调控菱面石墨烯多层膜中关联与拓扑相的关键调控旋钮。
英文摘要
Rhombohedral multilayer graphene hosts layer-polarized flat bands, providing an intriguing platform for correlated and topological electronic states; however, the role of layer number in governing symmetry breaking and surface screening remains elusive. Here we prepare rhombohedral graphene multilayers and systematically conduct electrical transport measurements. We uncover an unconventional layer dependence of phase transitions: the critical displacement field (D$_{c}$) for the layer-antiferromagnetic (LAF)-to-semimetal transitions remains constant across tetralayer to hexalayer graphene, whereas the D$_{c}$ for semimetal-to-layer-polarized-insulator (LPI) transition increases with layer number, defying unscreened Coulomb interaction models. In hexalayer graphene, surface-state-dominated transport emerges, with Landau levels (LLs) and resistive peaks selectively controlled by adjacent gates, a signature of strong interlayer screening absent in thinner stacks. High magnetic fields reveal valley-layer-locked LLs and dissipative states possibly from interlayer backscattering, highlighting the presence of decoupled surface states. Our findings establish layer number as a key tuning knob for engineering correlated and topological phases in rhombohedral graphene multilayers.
