2020年第67回応用物理学会春季学術講演会

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[12a-PA2-1~77] 17 ナノカーボン

2020年3月12日(木) 09:30 〜 11:30 PA2 (第3体育館)

09:30 〜 11:30

[12a-PA2-40] Direct tight-binding calculations of band structure of asymmetrically doped twisted multilayer graphene

Anton Visikovskiy1、Hitoshi Imamura1、Takashi Kajiwara1、Fumio Komori2、Satoru Tanaka1 (1.Kyushu Univ.、2.Univ. of Tokyo)

キーワード:graphene, band structure

Twisted bilayer graphene attracts the attention of surface science community lately due to prospects of isolated flat band formation at specific small twist angles (magic angles ~1o) and, as a consequence, strongly correlated electron behavior, including possible superconducting state. Unfortunately, the unit cell of such twisted bilayer consists of thousands of atoms and calculation of band structure is a formidable task. Simplified continuum tight-binding (TB) models has been introduced, however in these models it is difficult to account various atomic relaxation phenomena as well as difference in doping levels generally appearing in real life. Also, the band structure generated for extremely large supercell is difficult to compare directly with experimental ARPES data which usually acquired for conventional graphene Brillouin zone (BZ), not the folded supercell BZ. Here, we report direct TB calculations using atomistic Slater-Koster approach for twisted multilayer graphenes with realistic asymmetric doping levels and also unfolded band structure in direct comparison with ARPES observations. The reduction of the Fermi velocity and formation of minigaps is obvious from calculations.