扭曲双层双层石墨烯异质结构的隧穿特性

中文摘要 AI 辅助

通过实验和理论研究了以不同小角度扭曲的双层伯纳尔石墨烯片之间的电子隧穿。电流-电压特性呈现出共振峰、台阶以及负微分电阻区域，其成因可通过相邻层经能量和动量偏移的电子色散的交点来解释。对隧穿输运的理论分析表明，理解该现象的关键在于两种贡献的竞争：平行双层石墨烯片的同类（电导率-电导率或价带-价带）能带与异类（电导率-价带）能带之间的竞争。研究了隧穿电流模式随扭曲角增大的系统演化。结果显示，双层石墨烯内的位移场导致的电子波函数在石墨烯亚层间的极化会强烈影响隧穿概率，从而增强带边范霍夫奇点引发的负微分电阻。

英文摘要

Electron tunneling between sheets of bilayer Bernal graphene twisted at different small angles was studied experimentally and theoretically. The current-voltage characteristics exhibit resonant peaks, steps, and regions of negative differential resistance, the origin of which is explained by the intersections of energy- and momentum-shifted electron dispersions of adjacent layers. A theoretical analysis of tunneling transport demonstrated that the key to understanding this phenomenon lies in the competition between two contributions: between like (conductivity-conductivity or valence-valence) and unlike (conductivity-valence) bands of parallel bilayer graphene sheets. A systematic evolution of the tunneling current patterns with increase of the twist angle is investigated. Polarization of electron wave function across graphene sublayers caused by displacement field within bilayer graphene is shown to strongly affect the tunneling probability, thus enhancing negative differential resistance due to Van Hove singularities at the band edges.

发表机构

• Institute for Spectroscopy, Russian Academy of Sciences（俄罗斯科学院光谱学研究所）
• National Research University Higher School of Economics（高等经济国立研究大学）
• Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences（俄罗斯科学院微电子技术与高纯材料研究所）
• Programmable Functional Materials Lab, Center for Neurophysics and Neuromorphic Technologies（神经物理与类脑技术中心可编程功能材料实验室）
• Moscow Center for Advanced Studies（莫斯科高级研究中心）
• Department of Materials Science and Engineering, National University of Singapore（新加坡国立大学材料科学与工程系）
• Institute for Functional Intelligent Materials, National University of Singapore（新加坡国立大学功能智能材料研究所）

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