扭转石墨烯层间通过原子级精确势垒的耦合

中文摘要 AI 辅助

理解和控制范德华（vdW）材料中的层间耦合对于设计新型电子现象（包括关联态、拓扑相和超导电性）至关重要。扭转双层石墨烯（TBG）提供了一个高度可调的平台，用以探索层间取向和间距如何影响量子输运和莫尔物理。在此，我们提出一种方法，通过使用由超薄、厚度可调的六方氮化硼（hBN）间隔层分隔的双栅极器件，实现对TBG中层间耦合的精确、原子尺度控制。该方法能够系统性地控制层间相互作用，并证明在固定扭转角下，随着层间距增大，实现电子-空穴双层行为所需的临界位移场减小。值得注意的是，在小扭转角下，即使层间被四层hBN（约1.3纳米）隔开，与莫尔相关的边峰仍然存在，表明层间能带杂化具有鲁棒性。通过将原子层精度的层间耦合控制与独立的扭转角可调性相结合，我们的平台为发现由工程化层间耦合和莫尔图案调控的新型莫尔物理开辟了新途径。

英文摘要

Understanding and controlling interlayer coupling in van der Waals (vdW) materials is crucial for engineering novel electronic phenomena, including correlated states, topological phases, and superconductivity. Twisted bilayer graphene (TBG) offers a highly tunable platform to explore how interlayer orientation and separation influence quantum transport and moiré physics. Here, we introduce a method for achieving precise, atomic-scale control of interlayer coupling in TBG using dual-gated devices separated by ultrathin, thickness-tunable hBN spacers. This approach enables systematic control of interlayer interactions, demonstrating that the critical displacement field required for electron-hole bilayer behavior decreases as the layer separation increases at a fixed twist angle. Remarkably, at small twist angles, moiré-related side peaks persist even when layers are separated by tetralayers of hBN (approximately 1.3 nm), indicating robust interlayer band hybridization. By combining atomic-layer-precise control of interlayer coupling with independent twist angle tunability, our platform opens new avenues for discovering novel moiré physics governed by engineered interlayer coupling and moiré patterns.

发表机构

• The University of Hong Kong（香港大学）
• State Key Laboratory of Optical Quantum Materials, The University of Hong Kong（香港大学光学量子材料国家重点实验室）
• National Graphene Institute, University of Manchester（曼彻斯特大学国家石墨烯研究所）
• Department of Physics and Astronomy, University of Manchester（曼彻斯特大学物理与天文学系）
• Research Center for Electronic and Optical Materials, National Institute for Materials Science（物质材料研究机构电子与光学材料研究中心）
• Research Center for Materials Nanoarchitectonics, National Institute for Materials Science（物质材料研究机构材料纳米结构研究中心）

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