High temperature resistivity measured at ν = 5/2 as a predictor of 2DEG quality in the N=1 Landau level

Abstract

We report a high temperature (T = 0.3K) indicator of the excitation gap ${\Delta }_{5/2}$ at the filling factor $\nu =5/2$ fractional quantum Hall state in ultra-high quality AlGaAs/GaAs two-dimensional electron gases. As the lack of correlation between mobility $\mu$ and ${\Delta }_{5/2}$ has been well established in previous experiments, we define, analyze and discuss the utility of a different metric ${\rho }_{5/2}$, the resistivity at $\nu =5/2$, as a high temperature predictor of ${\Delta }_{5/2}$. This high-field resistivity reflects the scattering rate of composite fermions. Good correlation between ${\rho }_{5/2}$ and ${\Delta }_{5/2}$ is observed in both a density tunable device and in a series of identically structured wafers with similar density but vastly different mobility. This correlation can be explained by the fact that both ${\rho }_{5/2}$ and ${\Delta }_{5/2}$ are sensitive to long-range disorder from remote impurities, while $\mu$ is sensitive primarily to disorder localized near the quantum well.

11 pages, 4 figures

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• Limit to 2D mobility in modulation-doped GaAs quantum structures: How to achieve a mobility of 100 millions
• Modified MBE hardware and techniques and role of gallium purity for attainment of two dimensional electron gas mobility >35 x10^6 cm^2/Vs in AlGaAs/GaAs quantum wells grown by MBE
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Cited by in corpus (4)

• Mobility and quantum mobility of modern GaAs/AlGaAs heterostructures
• Quantum Lifetime in Ultra-High Quality GaAs Quantum Wells: Relationship to ${\Delta }_{5/2}$ and Impact of Density Fluctuations
• Fractional quantum Hall effect at the filling factor $\nu =5/2$
• Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport