High-temperature resistivity measured at 
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 as a predictor of the two-dimensional electron gas quality in the 
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 Landau level

Qian, Qi; Nakamura, James; Fallahi, Saeed; Gardner, G. C.; Watson, John; Manfra, Michael J.

doi:10.1103/physrevb.95.241304

Cited by 8 publications

(4 citation statements)

References 35 publications

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“…3 219 m 2 /Vs), whereas ρ 1/2 changes by 51% for the same Γ range, demonstrating that ρ 1/2 is more strongly correlated with the visibility of FQHEs. This result bears an intriguing similarity with the recent report that the resistivity at ν = 5/2 in the high-temperatures regime serves as an indicator of the strength of the ν = 5/2 FQHE that emerges at low temperatures [39]. Now we discuss the scattering mechanism that determines ρ 1/2 .…”

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confidence: 87%

Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport

Akiho,

Muraki

2022

Preprint

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We examine the impact of random potential due to remote impurites (RIs) and its in-situ controlled screening on fractional quantum Hall effects (FQHEs) around Landau-level filling factor ν = 1/2. The experiment is made possible by using a dual-gate GaAs quantum well (QW) that allows for the independent control of the density n e of the two-dimensional electron system in the QW and that (n SL ) of excess electrons in the modulationdoping superlattice. As the screening is reduced by decreasing n SL at a fixed n e , we observe a decrease in the apparent energy gap of the FQHEs deduced from thermal activation, which signifies a corresponding increase in the disorder broadening Γ of composite fermions (CFs). Interestingly, the increase in Γ is accompanied by a noticeable increase in the longitudinal resistivity at ν = 1/2 (ρ 1/2 ), with a much stronger correlation with Γ than electron mobility µ has. The in-situ control of RI screening enables us to disentangle the contributions of RIs and background impurities (BIs) to ρ 1/2 , with the latter in good agreement with the CF theory. We construct a scaling plot that helps in estimating the BI contribution to ρ 1/2 for a given set of n e and µ.

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confidence: 87%

Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport

Akiho,

Muraki

2022

Preprint

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“…A weaker particle-hole symmetric state at ν = 7/2 emerges given sufficient sample quality. Significant efforts on heterostructure design have been invested to enhance the quality of features observed and understand their interplay with disorder [16,[101][102][103][104][105]. Despite the observation of a new state at half filling, the fractional features in N = 1 of both odd and even denominator are much weaker than the lowest LL.…”

Section: Fractional Quantum Hall Effect In Higher Landau Levelsmentioning

confidence: 99%

A review of the quantum Hall effects in MgZnO/ZnO heterostructures

Falson

Kawasaki

2018

Rep. Prog. Phys.

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This review visits recent experimental efforts on high mobility two-dimensional electron systems (2DES) hosted at the Mg Zn[Formula: see text]O/ZnO heterointerface. We begin with the growth of these samples, and highlight the key characteristics of ozone-assisted molecular beam epitaxy required for their production. The transport characteristics of these structures are found to rival that of traditional semiconductor material systems, as signified by the high electron mobility ([Formula: see text] cm Vs) and rich quantum Hall features. Owing to a large effective mass and small dielectric constant, interaction effects are an order of magnitude stronger in comparison with the well studied GaAs-based 2DES. The strong correlation physics results in robust Fermi-liquid renormalization of the effective mass and spin susceptibility of carriers, which in turn dictates the parameter space for the quantum Hall effect. Finally, we explore the quantum Hall effect with a particular emphasis on the spin degree of freedom of carriers, and how their large spin splitting allows control of the ground states encountered at ultra-low temperatures within the fractional quantum Hall regime. We discuss in detail the physics of even-denominator fractional quantum Hall states, whose observation and underlying character remain elusive and exotic.

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“…[1][2][3][4][5][6][7][8][9] A more than 3000 times increase of the electron mobility over the last several decades lead to numerous important discoveries, including odd-10 and even- 11 denominator fractional quantum Hall effects, stripe and bubble phases, [12][13][14] exciton condensate in electron bilayers, 15 microwave-induced resistance oscillations and zero-resistance states, [16][17][18][19] etc. While there is growing experimental evidence that high mobility alone is not a good predictor of how a particular phenomenon manifests itself, 5,7,8,[20][21][22][23][24][25][26] there clearly exists a strong interest in further improvement of GaAs/Al x Ga 1−x As heterostructures. [6][7][8][9][27][28][29] It is therefore important to understand dominant sources of disorder and elucidate the ways to minimize them.…”

Section: Introductionmentioning

confidence: 99%

Mobility and quantum mobility of modern GaAs/AlGaAs heterostructures

Sammon

Zudov

Shklovskiǐ³

2018

Phys. Rev. Materials

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In modern GaAs/AlxGa1−xAs heterostructures with record high mobilities, a two-dimensional electron gas (2DEG) in a quantum well is provided by two remote donor δ-layers placed on both sides of the well. Each δ-layer is located within a narrow GaAs well, flanked by narrow AlAs layers which capture excess electrons from donors. We show that each excess electron is localized in a compact dipole atom with the nearest donor. Nevertheless, excess electrons screen both the remote donors and background impurities. When the fraction of remote donors filled by excess electrons f is small, the remote donor limited quantum mobility grows as f 3 and becomes larger than the background impurity limited one at a characteristic value fc. We also calculate both the mobility and the quantum mobility limited by the screened background impurities with concentrations N1 in AlxGa1−xAs and N2 in GaAs, which allows one to estimate N1 and N2 from the measured mobilities. Taken together, our findings should help to identify avenues for further improvement of modern heterostructures.

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High-temperature resistivity measured at ν=52 as a predictor of the two-dimensional electron gas quality in the N=1 Landau level

Cited by 8 publications

References 35 publications

Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport

Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport

A review of the quantum Hall effects in MgZnO/ZnO heterostructures

Mobility and quantum mobility of modern GaAs/AlGaAs heterostructures

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