Helical Edge States and Quantum Phase Transitions in Tetralayer Graphene
Shi Che, Yanmeng Shi, Jiawei Yang, Haidong Tian, Ruoyu Chen, Takashi Taniguchi, Kenji Watanabe, Dmitry Smirnov, Chun Ning Lau, Efrat Shimshoni, Ganpathy Murthy, Herbert A. Fertig
Helical conductors with spin-momentum locking are promising platforms for Majorana fermions. Here we report observation of two topologically distinct phases supporting helical edge states in charge neutral Bernal-stacked tetralayer graphene in Hall bar and Corbino geometries. As the magnetic field B and out-of-plane displacement field D are varied, we observe a phase diagram consisting of an insulating phase and two metallic phases, with 0, 1 and 2 helical edge states, respectively. These phases are accounted for by a theoretical model that relates their conductance to spin-polarization plateaus. Transitions between them arise from a competition among inter-layer hopping, electrostatic and exchange interaction energies. Our work highlights the complex competing symmetries and the rich quantum phases in few-layer graphene.
Real-space study of zero-field correlation in tetralayer rhombohedral graphene
Tsung-Dao Lee Institute, Shanghai Jiao Tong University（上海交大李政道研究所）；Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院人工结构与量子控制教育部重点实验室）；School of Physical Science and Technology, ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University（上海科技大学物质科学与技术学院拓扑物理实验室）；Research Center for Electronic and Optical Materials, National Institute for Materials Science（日本国立材料研究所电子光学材料研究中心）；Research Center for Materials Nanoarchitectonics, National Institute for Materials Science（日本国立材料研究所材料纳米构筑研究中心）；Hefei National Laboratory（合肥国家实验室）
Tunable high-Chern-number Chern insulators in rhombohedral tetralayer graphene/hBN moiré superlattices
State Key Laboratory of Micro-nano Engineering Science, Tsung-Dao Lee lnstitute & School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shanghai Jiao Tong University（上海交通大学微纳电子工程科学国家重点实验室、李政道研究所及物理与天文学院人工结构与量子控制教育部重点实验室）；Department of Physics, City University of Hong Kong（香港城市大学物理系）；Research Center for Electronic and Optical Materials, National Institute for Materials Science（国家材料研究所电子与光学材料研究中心）；Research Center for Materials Nanoarchitectonics, National Institute for Materials Science（国家材料研究所材料纳米结构研究中心）；Hefei National Laboratory（合肥国家实验室）；Shanghai Research Center for Quantum Sciences（上海量子科学研究中心）；Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong)（粤港澳大湾区量子科学中心（广东））；Department of Physics, Southern University of Science and Technology（南方科技大学物理系）；Department of Physics, Hong Kong University of Science and Technology（香港科技大学物理系）
Fermiology and the Candidate Chiral Superconductor in Rhombohedral Tetralayer Graphene
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory（斯坦福材料能源科学研究所，SLAC国家加速器实验室）；Department of Physics, Stanford University（斯坦福大学物理系）；Princeton University（普林斯顿大学）；Department of Materials Science and Engineering, Stanford University（斯坦福大学材料科学与工程系）；Research Center for Electronic and Optical Materials, National Institute for Materials Science（日本国立物质材料研究所电子与光学材料研究中心）；Research Center for Materials Nanoarchitectonics, National Institute for Materials Science（日本国立物质材料研究所材料纳米架构研究中心）
Electrostatic Screening Modulation of Graphene's Electronic Structure and the Helical Wavefunction Dominated Topological Properties
Key Laboratory of Extraordinary Bond Engineering and Advanced Materials Technology (EBEAM) of Chongqing, College of Mechanical and Electrical Engineering, Yangtze Normal University（重庆极端键合工程与先进材料技术重点实验室，长江师范学院机电工程学院）
Up/down-conversion of infrared light by few-layer graphene polytypes
National Graphene Institute, University of Manchester（国家石墨烯研究所，曼彻斯特大学）；Department of Physics & Astronomy, University of Manchester（曼彻斯特大学物理与天文系）；Department of Physics, University of Osaka（大阪大学物理系）；Center for Integrated Science and Humanities, Fukushima Medical University（福岛医科大学综合科学与人文学中心）；Institute for Solid State Physics, The University of Tokyo（东京大学固体物理研究所）
Thermal Strain-Driven Periodic Ripples in Ultrathin Sb2Te3/Graphene Heterostructures and their Implications for Strain Engineering
Universidad de Chile（智利大学）；CEDENNA；Universidad Adolfo Ibáñez（阿道夫·伊巴涅斯大学）；Stanford University（斯坦福大学）；Universidad Técnica Federico Santa María（弗雷德里科·圣塔玛利亚技术大学）
Supermoiré reconstruction and domain-resolved valley topology in helical multilayer graphene
Seoul National University（首尔大学）；Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST（加泰罗尼亚纳米科学和纳米技术研究所（ICN2，西班牙高等科学研究委员会和巴塞罗那独立系统大学））；University of Seoul（首尔大学）
Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel（格勒诺布尔阿尔卑斯大学）；LPMMC, Univ. Grenoble Alpes（格勒诺布尔阿尔卑斯大学）；Research Center for Electronic and Optical Materials, National Institute for Materials Science（物质材料研究所）；Research Center for Materials Nanoarchitectonics, National Institute for Materials Science（物质材料研究所）；Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG-Pheliqs（格勒诺布尔阿尔卑斯大学）；Liaoning Academy of Materials（辽宁省材料研究院）；State Key Laboratory of Quantum Optics Technologies and Devices, Institute of Optoelectronics, Shanxi University（山西大学）；Collaborative Innovation Center of Extreme Optics, Shanxi University（山西大学）
