Superlattice-Induced Insulating States and Valley-Protected Orbits in Twisted Bilayer Graphene

被引：362

作者：

Cao, Y. ^{[1
]}

Luo, J. Y. ^{[1
]}

Fatemi, V. ^{[1
]}

Fang, S. ^{[2
]}

Sanchez-Yamagishi, J. D. ^{[2
]}

Watanabe, K. ^{[3
]}

Taniguchi, T. ^{[3
]}

Kaxiras, E. ^{[2
,4
]}

Jarillo-Herrero, P. ^{[1
]}

机构：

[1] MIT, Dept Phys, Cambridge, MA 02139 USA

[2] Harvard Univ, Dept Phys, Cambridge, MA 02138 USA

[3] Natl Inst Mat Sci, Namiki 1-1, Tsukuba, Ibaraki 3050044, Japan

[4] Harvard Univ, John A Paulson Sch Engn & Appl Sci, Cambridge, MA 02138 USA

来源：

PHYSICAL REVIEW LETTERS | 2016年 / 117卷 / 11期

基金：

美国国家科学基金会;

关键词：

DER-WAALS HETEROSTRUCTURES; HEXAGONAL BORON-NITRIDE; VAN-HOVE SINGULARITIES; TRANSITION;

D O I：

10.1103/PhysRevLett.117.116804

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Twisted bilayer graphene (TBLG) is one of the simplest van der Waals heterostructures, yet it yields a complex electronic system with intricate interplay between moire physics and interlayer hybridization effects. We report on electronic transport measurements of high mobility small angle TBLG devices showing clear evidence for insulating states at the superlattice band edges, with thermal activation gaps several times larger than theoretically predicted. Moreover, Shubnikov-de Haas oscillations and tight binding calculations reveal that the band structure consists of two intersecting Fermi contours whose crossing points are effectively unhybridized. We attribute this to exponentially suppressed interlayer hopping amplitudes for momentum transfers larger than the moire wave vector.

引用

页数：5

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