Increasing the ν = 5 / 2 gap energy: an analysis of MBE growth parameters

Abstract

The fractional quantized Hall state (FQHS) at the filling factor ν = 5/2 is of special interest due to its possible application for quantum computing. Here we report on the optimization of growth parameters that allowed us to produce two-dimensional electron gases (2DEGs) with a 5/2 gap energy up to 135 mK. We concentrated on optimizing the MBE growth to provide high 5/2 gap energies in "as-grown" samples, without the need to enhance the 2DEGs properties by illumination or gating techniques. Our findings allow us to analyse the impact of doping in narrow quantum wells with respect to conventional DX-doping in AlxGa1-xAs. The impact of the setback distance between doping layer and 2DEG was investigated as well. Additionally, we found a considerable increase in gap energy by reducing the amount of background impurities. To this end growth techniques like temperature reductions for substrate and effusion cells and the reduction of the Al mole fraction in the 2DEG region were applied.

References in corpus (7)

• Non-Abelian Anyons and Topological Quantum Computation
• Experimental studies of the fractional quantum Hall effect in the first excited Landau level
• Fractional Quantum Hall Effect in the Second Landau Level
• Limit to 2D mobility in modulation-doped GaAs quantum structures: How to achieve a mobility of 100 millions
• Intrinsic Gap of the nu=5/2 Fractional Quantum Hall State
• Tilt-Induced Anisotropic to Isotropic Phase Transition at $\nu =5/2$
• Gating of high-mobility two-dimensional electron gases in GaAs/AlGaAs heterostructures

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• Low-temperature illumination and annealing of ultra-high quality quantum wells
• Nonequilibrium transport in density-modulated phases of the second Landau level
• Josephson-like tunnel resonance and large Coulomb drag in GaAs-based electron-hole bilayers
• Improvement of the transport properties of a high-mobility electron system by intentional parallel conductance
• Prediction of non-Abelian fractional quantum Hall effect at $\nu =2+\frac{4}{11}$
• Fractional quantum Hall effect at the filling factor $\nu =5/2$
• Competition of Pairing and Nematicity in the Two-Dimensional Electron Gas
• Disorder broadening of even denominator fractional quantum Hall states in the presence of a short-range alloy potential