Quantitative Transport Measurements of Fractional Quantum Hall Energy Gaps in Edgeless Graphene Devices.
Phys Rev Lett
; 121(22): 226801, 2018 Nov 30.
Article
en En
| MEDLINE
| ID: mdl-30547606
ABSTRACT
Owing to their wide tunability, multiple internal degrees of freedom, and low disorder, graphene heterostructures are emerging as a promising experimental platform for fractional quantum Hall (FQH) studies. Here, we report FQH thermal activation gap measurements in dual graphite-gated monolayer graphene devices fabricated in an edgeless Corbino geometry. In devices with substrate-induced sublattice splitting, we find a tunable crossover between single- and multicomponent FQH states in the zero energy Landau level. Activation gaps in the single-component regime show excellent agreement with numerical calculations using a single broadening parameter Γ≈7.2 K. In the first excited Landau level, in contrast, FQH gaps are strongly influenced by Landau level mixing, and we observe an unexpected valley-ordered state at integer filling ν=-4.
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MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Año:
2018
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Article
País de afiliación:
Estados Unidos