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Available under license: CC BY: Creative Commons Attribution 4.0 International License
Final published version
Licence: CC BY: Creative Commons Attribution 4.0 International License
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Edge currents shunt the insulating bulk in gapped graphene
AU - Zhu, M. J.
AU - Kretinin, A. V.
AU - Thompson, Michael Dermot
AU - Bandurin, D. A.
AU - Hu, S.
AU - Yu, G. L.
AU - Birkbeck, J.
AU - Mishchenko, Artem
AU - Vera-Marun, I. J.
AU - Watanabe, K.
AU - Taniguchi, T.
AU - Polini, M.
AU - Prance, Jonathan Robert
AU - Novoselov, K. S.
AU - Geim, A. K.
AU - Ben Shalom, M.
PY - 2017/2/17
Y1 - 2017/2/17
N2 - An energy gap can be opened in the spectrum of graphene reaching values as large as 0.2 eV in the case of bilayers. However, such gaps rarely lead to the highly insulating state expected at low temperatures. This long-standing puzzle is usually explained by charge inhomogeneity. Here we revisit the issue by investigating proximity-induced superconductivity in gapped graphene and comparing normal-state measurements in the Hall bar and Corbino geometries. We find that the supercurrent at the charge neutrality point in gapped graphene propagates along narrow channels near the edges. This observation is corroborated by using the edgeless Corbino geometry in which case resistivity at the neutrality point increases exponentially with increasing the gap, as expected for an ordinary semiconductor. In contrast, resistivity in the Hall bar geometry saturates to values of about a few resistance quanta. We attribute the metallic-like edge conductance to a nontrivial topology of gapped Dirac spectra.
AB - An energy gap can be opened in the spectrum of graphene reaching values as large as 0.2 eV in the case of bilayers. However, such gaps rarely lead to the highly insulating state expected at low temperatures. This long-standing puzzle is usually explained by charge inhomogeneity. Here we revisit the issue by investigating proximity-induced superconductivity in gapped graphene and comparing normal-state measurements in the Hall bar and Corbino geometries. We find that the supercurrent at the charge neutrality point in gapped graphene propagates along narrow channels near the edges. This observation is corroborated by using the edgeless Corbino geometry in which case resistivity at the neutrality point increases exponentially with increasing the gap, as expected for an ordinary semiconductor. In contrast, resistivity in the Hall bar geometry saturates to values of about a few resistance quanta. We attribute the metallic-like edge conductance to a nontrivial topology of gapped Dirac spectra.
U2 - 10.1038/ncomms14552
DO - 10.1038/ncomms14552
M3 - Journal article
VL - 8
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
M1 - 14552
ER -