Fractional Quantum Hall States in Bilayer Graphene Probed by Transconductance Fluctuations

被引：36

作者：

Kim, Youngwook ^{[1
,2
]}

Lee, Dong Su ^{[3
]}

Jung, Suyong ^{[4
]}

Skakalova, Viera ^{[5
,6
]}

Taniguchi, T. ^{[7
]}

Watanabe, K. ^{[7
]}

Kim, Jun Sung ^{[1
]}

Smet, Jurgen H. ^{[2
]}

机构：

[1] Pohang Univ Sci & Technol, Dept Phys, Pohang 790784, South Korea

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

[3] KIST Jeonbuk Inst Adv Composite Mat, Jeonbuk 565905, South Korea

[4] Korea Res Inst Stand & Sci, Ctr Quantum Measurement Sci, Taejon 305340, South Korea

[5] Univ Vienna, Fac Phys, A-1090 Vienna, Austria

[6] STU Ctr Nanodiagnost, Bratislava 81243, Slovakia

[7] Natl Inst Mat Sci, Adv Mat Lab, Tsukuba, Ibaraki 3050044, Japan

来源：

NANO LETTERS | 2015年 / 15卷 / 11期

基金：

新加坡国家研究基金会;

关键词：

Bilayer graphene; transconductance fluctuations; fractional quantum Hall states; electron-hole symmetry; BROKEN-SYMMETRY STATES; QUASI-PARTICLES; BERRYS PHASE; LOCALIZATION; CHARGE; EXCITATIONS;

D O I：

10.1021/acs.nanolett.5b02876

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

We have investigated fractional quantum Hall (QH) states in Bernal-stacked bilayer graphene using trans-conductance fluctuation measurements. A variety of odd-denominator fractional QH states with nu(QH) --> nu(QH) + 2 symmetry, as previously reported, are observed. However, surprising is that also particle-hole symmetric states are clearly resolved in the same measurement set. We attribute their emergence to the reversal of orbital states in the octet level scheme induced by a strong local charge imbalance, which can be captured by the transconductance fluctuations. Also the even-denominator fractional QH state at filling -1/2 is observed. However, contrary to a previous study on a suspended graphene layer [Ki et al. Nano Lett. 2014, 14, 2135], the particle-hole symmetric state at filling 1/2 is detected as well. These observations suggest that the stability of both odd and even denominator fractional QH states is very sensitive to local transverse electric fields in bilayer graphene.

引用

页码：7445 / 7451

页数：7

共 45 条

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