Probing the excited subband dispersion of holes confined to GaAs wide quantum wells

ORAL

Abstract

Owing to the strong spin-orbit coupling and their large effective mass, the two-dimensional (2D) holes in modulation-doped GaAs quantum wells provide a fertile test bed to study the rich physics of low-dimensional systems. In a wide quantum well, even at moderate 2D densities, the holes start to occupy the excited subband, a subband whose dispersion is very unusual and has a non-monotonic dependence on the wave vector. Here, we study a 2D hole system confined to a 40-nm-thick (001) GaAs quantum well and demonstrate that, via the application of both front and back gates, the density can be tuned in a wide range, between \textasciitilde 1 and 2 \texttimes 10$^{\mathrm{11}}$ cm$^{\mathrm{-2}}$. Using Fourier analysis of the low-field Shubnikov-de Haas oscillations, we investigate the population of holes and the spin-orbit interaction induced spin-splitting in different subbands. We discuss the results in light of self-consistent quantum calculations of magneto-oscillations.

*Work support by the DOE BES (DE-FG02-00-ER45841), the NSF (Grants DMR-1305691 and MRSEC DMR-1420541), the Gordon and Betty Moore Foundation (Grant GBMF4420), and Keck Foundation for experiments, and the NSF Grant DMR-1310199 for calculations.

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Authors

  • Insun Jo

    • Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544
    • Dept. of Electrical Engineering, Princeton University, Princeton, NJ08544, USA

  • Yang Liu

    • Dept. of Electrical Engineering, Princeton University, Princeton, NJ08544, USA

  • H. Deng

    • Dept. of Electrical Engineering, Princeton University, Princeton, NJ08544, USA

  • M. Shayegan

    • Dept. of Electrical Engineering, Princeton University, Princeton, NJ08544, USA

  • L. N. Pfeiffer

    • Dept. of Electrical Engineering, Princeton University, Princeton, NJ08544, USA

  • K. W. West

    • Dept. of Electrical Engineering, Princeton University, Princeton, NJ08544, USA

  • K. W. Baldwin

    • Dept. of Electrical Engineering, Princeton University, Princeton, NJ08544, USA

  • R. Winkler

    • Dept. of Physics, Northern Illinois University, Dekalb, IL 60115, USA