Marginal metallic state at a fractional filling of ’8/5’ and ’4/3’ of Landau levels in the GaAs/AlGaAs 2D electron system

Mani, R. G.; Wijewardena, U. Kushan; Nanayakkara, Tharanga; Kriisa, Annika; Reichl, Christian; Wegscheider, Werner

doi:10.1038/s41598-021-94563-0

Cited by 2 publications

(2 citation statements)

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“…2 , marked by black horizontal line segments with colored arrows within them, for the disappearance of the “4/3” and “7/5” FQHE’s. A recent microwave power and temperature dependent study suggests that odd denominator rational fractional fillings of Landau levels, where the minima disappear in a crossover range of tilt angles, exhibit so-called marginal metallic states, which are characterized by a profound temperature/microwave power insensitivity in the diagonal resistance 37 . In such a marginal metallic state, carrier, or composite fermion 29 , interaction with the boundary is likely to determine size effects.…”

Section: Discussionmentioning

confidence: 99%

“…2 a, c and e. As the localization length becomes larger on from either side, the narrowest device first satisfies the condition . Upon realizing this condition, carriers in this device are effectively delocalized as they interact with the boundary, this Hall bar becomes “metallic,” which leads to the vanishing of the resistance minimum and a temperature- or microwave power- independent diagonal resistance 37 . A closer approach to increases the localization length further such that the specimen is the next to become “metallic,” followed by the device with an even closer approach to .…”

Section: Discussionmentioning

confidence: 99%

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Size dependence- and induced transformations- of fractional quantum Hall effects under tilted magnetic fields

Wijewardena

Nanayakkara

Kriisa

et al. 2022

Sci Rep

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Two-dimensional electron systems subjected to high transverse magnetic fields can exhibit Fractional Quantum Hall Effects (FQHE). In the GaAs/AlGaAs 2D electron system, a double degeneracy of Landau levels due to electron-spin, is removed by a small Zeeman spin splitting, $$g \mu _B B$$ g μ B B , comparable to the correlation energy. Then, a change of the Zeeman splitting relative to the correlation energy can lead to a re-ordering between spin polarized, partially polarized, and unpolarized many body ground states at a constant filling factor. We show here that tuning the spin energy can produce fractionally quantized Hall effect transitions that include both a change in $$\nu$$ ν for the $$R_{xx}$$ R xx minimum, e.g., from $$\nu = 11/7$$ ν = 11 / 7 to $$\nu = 8/5$$ ν = 8 / 5 , and a corresponding change in the $$R_{xy}$$ R xy , e.g., from $$R_{xy}/R_{K} = (11/7)^{-1}$$ R xy / R K = ( 11 / 7 ) - 1 to $$R_{xy}/R_{K} = (8/5)^{-1}$$ R xy / R K = ( 8 / 5 ) - 1 , with increasing tilt angle. Further, we exhibit a striking size dependence in the tilt angle interval for the vanishing of the $$\nu = 4/3$$ ν = 4 / 3 and $$\nu = 7/5$$ ν = 7 / 5 resistance minima, including “avoided crossing” type lineshape characteristics, and observable shifts of $$R_{xy}$$ R xy at the $$R_{xx}$$ R xx minima- the latter occurring for $$\nu = 4/3, 7/5$$ ν = 4 / 3 , 7 / 5 and the 10/7. The results demonstrate both size dependence and the possibility, not just of competition between different spin polarized states at the same $$\nu$$ ν and $$R_{xy}$$ R xy , but also the tilt- or Zeeman-energy-dependent- crossover between distinct FQHE associated with different Hall resistances.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Size dependence- and induced transformations- of fractional quantum Hall effects under tilted magnetic fields

Wijewardena

Nanayakkara

Kriisa

et al. 2022

Sci Rep

Self Cite

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Non-equilibrium excited-state fractionally quantized Hall effects observed via current bias spectroscopy

Wijewardena,

Mani,

Kriisa

et al. 2024

Commun Phys

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Studies of fractional quantum Hall effects (FQHE) across various two-dimensional electronic systems (2DES) have helped to establish the equilibrium FQHE many-body ground states with fractionally charged excitations and composite particles in condensed matter. Then, the question arises whether an FQHE system driven to non-equilibrium can approach a different stationary state from the known equilibrium FQHE states. To investigate this question, we examine FQHE over filling factors, ν, 2 ≥ ν ≥ 1 under non-equilibrium finite bias conditions realized with a supplementary dc-current bias, I DC , in high mobility GaAs/AlGaAs devices. Here, we show that all observable canonical equilibrium FQHE resistance minima at |I DC | = 0 undergo bimodal splitting vs. I DC , yielding branch-pairs and diamond shapes in color plots of the diagonal resistance, as canonical FQHE are replaced, with increasing I DC , by excited-state fractionally quantized Hall effects at branch intersections. A tunneling model serves to interpret the results.

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Marginal metallic state at a fractional filling of ’8/5’ and ’4/3’ of Landau levels in the GaAs/AlGaAs 2D electron system

Abstract: A metallic state with a vanishing activation gap, at a filling factor $$\nu = 8/5$$ ν = 8 / 5 in the untilted specimen with $$n= 2 \times 10^{11} cm^{-2}$$ n = 2 × 10 11 … Show more

Cited by 2 publications

References 42 publications

Size dependence- and induced transformations- of fractional quantum Hall effects under tilted magnetic fields

Size dependence- and induced transformations- of fractional quantum Hall effects under tilted magnetic fields

Non-equilibrium excited-state fractionally quantized Hall effects observed via current bias spectroscopy

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