Broken-Symmetry Quantum Hall States in Twisted Bilayer Graphene

被引：13

作者：

Kim, Youngwook ^{[1
,8
]}

Park, Jaesung ^{[2
]}

Song, Intek ^{[3
,4
]}

Ok, Jong Mok ^{[1
]}

Jo, Younjung ^{[5
]}

Watanabe, Kenji ^{[6
]}

Taniquchi, Takashi ^{[6
]}

Choi, Hee Cheul ^{[3
,4
]}

Lee, Dong Su ^{[7
]}

Jung, Suyong ^{[2
]}

Kim, Jun Sung ^{[1
]}

机构：

[1] Pohang Univ Sci & Technol, Dept Phys, Pohang 37673, South Korea

[2] Korea Res Inst Stand & Sci, Daejeon 305340, South Korea

[3] Inst for Basic Sci Korea, Ctr Artificial Low Dimens Elect Syst, Pohang 37673, South Korea

[4] Pohang Univ Sci & Technol, Dept Chem, Pohang 37673, South Korea

[5] Kyungpook Natl Univ, Dept Phys, Daegu 702701, South Korea

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

[7] KIST Jeonbuk Inst Adv Composite Mat, Appl Quantum Composites Res Ctr, Jeonbuk 55324, South Korea

[8] Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany

来源：

SCIENTIFIC REPORTS | 2016年 / 6卷

基金：

美国国家科学基金会; 新加坡国家研究基金会;

关键词：

PHASE-TRANSITION; FERROMAGNETISM; SPIN;

D O I：

10.1038/srep38068

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：

Twisted bilayer graphene offers a unique bilayer two-dimensional-electron system where the layer separation is only in sub-nanometer scale. Unlike Bernal-stacked bilayer, the layer degree of freedom is disentangled from spin and valley, providing eight-fold degeneracy in the low energy states. We have investigated broken-symmetry quantum Hall (QH) states and their transitions due to the interplay of the relative strength of valley, spin and layer polarizations in twisted bilayer graphene. The energy gaps of the broken-symmetry QH states show an electron-hole asymmetric behaviour, and their dependence on the induced displacement field are opposite between even and odd filling factor states. These results strongly suggest that the QH states with broken valley and spin symmetries for individual layer become hybridized via interlayer tunnelling, and the hierarchy of the QH states is sensitive to both magnetic field and displacement field due to charge imbalance between layers.

引用

页数：8

共 37 条

[1] MAGNETIC-FIELD-DRIVEN DESTRUCTION OF QUANTUM HALL STATES IN A DOUBLE QUANTUM-WELL [J].