Fractional Quantum Hall States in Bilayer Graphene Probed by Transconductance Fluctuations

Autor(en)

Youngwook Kim, Dong Su Lee, Suyong Jung, Viera Skakalova, T. Taniguchi, K. Watanabe, Jun Sung Kim, Jurgen H. Smet

Abstrakt

We have investigated fractional quantum Hall (QH) states in Bernal-stacked bilayer graphene using transconductance fluctuation measurements. A variety of odd-denominator fractional QH states with ν

_QH → ν

_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.

Organisation(en)

Institut für Ostasienwissenschaften, Physik Nanostrukturierter Materialien

Externe Organisation(en)

Pohang University of Science and Technology (POSTECH), Max-Planck-Institut für Festkörperforschung, Korea Institute of Science and Technology (KIST), Korea Research Institute of Standards & Science (KRISS), Slovak University of Technology in Bratislava, National Institute for Materials Science

Journal

Nano Letters: a journal dedicated to nanoscience and nanotechnology

Band

15

Seiten

7445-7451

Anzahl der Seiten

7

ISSN

1530-6984

DOI

https://doi.org/10.1021/acs.nanolett.5b02876

Publikationsdatum

11-2015

Peer-reviewed

Ja

ÖFOS 2012

103018 Materialphysik

Schlagwörter

ASJC Scopus Sachgebiete

Condensed Matter Physics, Mechanical Engineering, Bioengineering, Allgemeine Chemie, Allgemeine Materialwissenschaften

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/7cff3f30-ad30-48b2-a9e1-080e719ee90f