Density-dependent two-dimensional optimal mobility in ultra-high-quality semiconductor quantum wells

Abstract

We calculate using the Boltzmann transport theory the density dependent mobility of two-dimensional (2D) electrons in GaAs, SiGe and AlAs quantum wells as well as of 2D holes in GaAs quantum wells. The goal is to precisely understand the recently reported breakthrough in achieving a record 2D mobility for electrons confined in a GaAs quantum well. Comparing our theory with the experimentally reported electron mobility in GaAs quantum wells, we conclude that the mobility is limited by unintentional background random charged impurities at an unprecedented low concentration of $\sim 10^{13}{\mathrm{cm}}^{-3}$. We find that this same low level of background disorder should lead to 2D GaAs hole and 2D AlAs electron mobilities of $\sim 10^7{\mathrm{cm}}^2/Vs$ and $\sim 4\times 10^7{\mathrm{cm}}^2/Vs$, respectively, which are much higher theoretical limits than the currently achieved experimental values in these systems. We therefore conclude that the current GaAs hole and AlAs electron systems are much dirtier than the state of the arts 2D GaAs electron systems. We present theoretical results for 2D mobility as a function of density, effective mass, quantum well width, and valley degeneracy, comparing with experimental data.

6 pages, 4 figures, 1 table

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Cited by in corpus (10)

• Understanding limits to mobility in ultra-high-mobility GaAs two-dimensional electron systems: The quest for 100 million cm${}^2$/Vs and beyond
• Hydrodynamics, viscous electron fluid, and Wiedeman-Franz law in 2D semiconductors
• Record-quality GaAs two-dimensional hole systems
• Scattering mechanisms in state-of-the-art GaAs/AlGaAs quantum wells
• Gate-defined Two-dimensional Hole and Electron Systems in an Undoped InSb Quantum Well
• Fractional quantum Hall effect at the filling factor $\nu =5/2$
• On the zero-field quantization of the anomalous quantum Hall effect in moiré 2D layers
• Valley polarization transition in a two-dimensional electron gas
• Bound state-continuum resonance transition in a shallow quantum well
• Disorder-induced strong-field strong-localization in 2D systems