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arXiv 2602.02692cond-mat.mes-hallcond-mat.str-el
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双层石墨烯中的应变电子学和扭转电子学

Straintronics and twistronics in bilayer graphene

IMDEA Nanoscience(IMDEA纳米科学研究所);Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University(武汉大学物理科学与技术学院人工微纳结构教育部重点实验室);School of Artificial Intelligence, Wuhan University(武汉大学人工智能学院);Wuhan Institute of Quantum Technology(武汉量子技术研究院);Donostia International Physics Center(圣塞巴斯蒂安国际物理中心)

Federico Escudero, Dong Wang, Pierre A. Pantaleón, Shengjun Yuan, Francisco Guinea, Zhen Zhan

AI总结:

通过全局方法构建任意扭转和异质应变的共格超胞,结合原子紧束缚和应变扩展连续模型,研究应变类型、大小、方向和晶格弛豫对带宽和拓扑的影响,发现剪切应变比单轴应变产生更强畸变,应变可驱动拓扑相变,为平带和拓扑现象提供可调平台。

摘要:

双层石墨烯中扭转和应变的相互作用使得形成莫尔条纹和窄带成为可能,这些窄带承载着关联和拓扑相。虽然魔角扭转双层石墨烯已被广泛研究,但应变为能带工程提供了额外且实际的控制手段。在这项工作中,我们首先生成一种全局方法来构建任意扭转和异质应变的共格超胞。然后,使用原子紧束缚和应变扩展连续模型研究共格结构,我们确定了最小化带宽(超越魔角)的构型。结果揭示了带窄化和拓扑对应变类型、大小、方向和晶格弛豫的强烈依赖性。特别是,剪切应变比单轴应变产生更强的畸变。通过自洽哈特里势包含电子-电子相互作用表明,应变展宽了裸带,同时减少了静电重整化。应变还驱动拓扑转变,因为窄带和远程带发生杂化,从而将扭转和应变双层石墨烯确立为平带和拓扑现象的可调平台。

英文摘要:

The interplay of twist and strain in bilayer graphene enables the formation of moiré patterns and narrow bands that host correlated and topological phases. While magic-angle twisted bilayer graphene has been widely studied, strain provides an additional and realistic control knob for band engineering. In this work, we first generate a global method to construct commensurate supercells for arbitrary twist and heterostrain. Then, using atomistic tight-binding and strain-extended continuum models to study the commensurate structures, we identify configurations that minimize the bandwidth beyond the magic angle. The results reveal a strong dependence of band narrowing and topology on strain type, magnitude, direction and lattice relaxation. Particularly, shear strain produces a stronger distortion than uniaxial strain. Including electron-electron interactions through a self-consistent Hartree potential shows that strain broadens the bare bands while reducing electrostatic renormalization. Strain also drives topological transitions as the narrow and remote bands hybridize, establishing twisted and strained bilayer graphene as a tunable platform for flat-band and topological phenomena.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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