Minibands in twisted bilayer graphene probed by magnetic focusing

被引：29

作者：

Berdyugin, A., I ^{[1
]}

Tsim, B. ^{[1
,2
]}

Kumaravadivel, P. ^{[1
,2
]}

Xu, S. G. ^{[1
,2
]}

Ceferino, A. ^{[1
,2
]}

Knothe, A. ^{[2
]}

Kumar, R. Krishna ^{[1
,2
]}

Taniguchi, T. ^{[3
]}

Watanabe, K. ^{[3
]}

Geim, A. K. ^{[1
,2
]}

Grigorieva, I., V ^{[1
,2
,4
]}

Fal'ko, V., I ^{[1
,2
,4
]}

机构：

[1] Univ Manchester, Sch Phys & Astron, Manchester M13 9PL, Lancs, England

[2] Univ Manchester, Natl Graphene Inst, Manchester M13 9PL, Lancs, England

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

[4] Henry Royce Inst Adv Mat, Manchester M13 9PL, Lancs, England

来源：

SCIENCE ADVANCES | 2020年 / 6卷 / 16期

基金：

英国工程与自然科学研究理事会;

关键词：

BLOCH OSCILLATIONS; MOIRE BANDS;

D O I：

10.1126/sciadv.aay7838

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Magnetic fields force ballistic electrons injected from a narrow contact to move along skipping orbits and form caustics. This leads to pronounced resistance peaks at nearby voltage probes as electrons are effectively focused inside them, a phenomenon known as magnetic focusing. This can be used not only for the demonstration of ballistic transport but also to study the electronic structure of metals. Here, we use magnetic focusing to probe narrowbands in graphene bilayers twisted at similar to 2 degrees.Their minibands are found to support long-range ballistic transport limited at low temperatures by intrinsic electron-electron scattering. A voltage bias between the layers causes strong minivalley splitting and allows selective focusing for different minivalleys, which is of interest for using this degree of freedom in frequently discussed valleytronics.

引用

页数：5

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