TY - JOUR

T1 - Observation of Even Denominator Fractional Quantum Hall Effect in Suspended Bilayer Graphene

AU - Ki, Dong-Keun

AU - Falko, Vladimir

AU - Abanin, Dmitry A.

AU - Morpurgo, Alberto F.

PY - 2014/4/9

Y1 - 2014/4/9

N2 - We investigate low-temperature magneto-transport in recently developed, high-quality multiterminal suspended bilayer graphene devices, enabling the independent measurement of the longitudinal and transverse resistance. We observe clear signatures of the fractional quantum Hall effect with different states that are either fully developed, and exhibit a clear plateau in the transverse resistance with a concomitant dip in longitudinal resistance or incipient, and exhibit only a longitudinal resistance minimum. All observed states scale as a function of filling factor v, as expected. An unprecedented even-denominator fractional state is observed at v = 1/2 on the hole side, exhibiting a clear plateau in R-xy quantized at the expected value of 2h/e(2) with a precision of similar to 0.5%. Many of our observations, together with a recent electronic compressibility measurement performed in graphene bilayers on hexagonal boron-nitride (hBN) substrates, are consistent with a recent theory that accounts for the effect of the degeneracy between the N = 0 and N = 1 Landau levels in the fractional quantum Hall effect and predicts the occurrence of a Moore-Read type v = 1/2 state. Owing to the experimental flexibility of bilayer graphene, which has a gate-dependent band structure, can be easily accessed by scanning probes, and can be contacted with materials such as superconductors, our findings offer new possibilities to explore the microscopic nature of even-denominator fractional quantum Hall effect.

AB - We investigate low-temperature magneto-transport in recently developed, high-quality multiterminal suspended bilayer graphene devices, enabling the independent measurement of the longitudinal and transverse resistance. We observe clear signatures of the fractional quantum Hall effect with different states that are either fully developed, and exhibit a clear plateau in the transverse resistance with a concomitant dip in longitudinal resistance or incipient, and exhibit only a longitudinal resistance minimum. All observed states scale as a function of filling factor v, as expected. An unprecedented even-denominator fractional state is observed at v = 1/2 on the hole side, exhibiting a clear plateau in R-xy quantized at the expected value of 2h/e(2) with a precision of similar to 0.5%. Many of our observations, together with a recent electronic compressibility measurement performed in graphene bilayers on hexagonal boron-nitride (hBN) substrates, are consistent with a recent theory that accounts for the effect of the degeneracy between the N = 0 and N = 1 Landau levels in the fractional quantum Hall effect and predicts the occurrence of a Moore-Read type v = 1/2 state. Owing to the experimental flexibility of bilayer graphene, which has a gate-dependent band structure, can be easily accessed by scanning probes, and can be contacted with materials such as superconductors, our findings offer new possibilities to explore the microscopic nature of even-denominator fractional quantum Hall effect.

KW - Even-denominator fractional quantum Hall effect

KW - multiterminal suspended bilayer graphene

KW - Non-Abelian Moore-Read state

KW - BROKEN-SYMMETRY STATES

KW - CHARGE

KW - TRANSPORT

KW - DEVICES

KW - PHASE

U2 - 10.1021/nl5003922

DO - 10.1021/nl5003922

M3 - Journal article

VL - 14

SP - 2135

EP - 2139

JO - Nano Letters

JF - Nano Letters

SN - 1530-6984

IS - 4

ER -