We report on transport characteristics of field effect two-dimensional electron gases (2DEGs) in surface indium antimonide quantum wells. The topmost 5 nm of the 30 nm wide quantum well is doped and shown to promote the formation of reliable, low resistance Ohmic contacts to surface InSb 2DEGs. High quality single-subband magnetotransport with clear quantized integer quantum Hall plateaus is observed to filling factor ν = 1 in magnetic fields of up to B = 18 T. We show that the electron density is gate-tunable, reproducible, and stable from pinch-off to 4 × 10 11 cm-2, and peak mobilities exceed 24 000 cm2/V s. Large Rashba spin-orbit coefficients up to 110 meV ·Å are obtained through weak anti-localization measurements. An effective mass of 0.019me is determined from temperature-dependent magnetoresistance measurements, and a g-factor of 41 at a density of 3.6 × 10 11 cm-2 is obtained from coincidence measurements in tilted magnetic fields. By comparing two heterostructures with and without a delta-doped layer beneath the quantum well, we find that the carrier density is stable with time when doping in the ternary Al0.1In0.9Sb barrier is not present. Finally, the effect of modulation doping on structural asymmetry between the two heterostructures is characterized.
|Journal||Applied Physics Letters|
|State||Published - 2 Jan 2023|
Bibliographical noteFunding Information:
The authors thank Christine Nicoll for useful discussions. E.A.B. acknowledges support from a Mike and Ophelia Lazaridis Fellowship. This research was undertaken thanks in part to funding from the Canada First Research Excellence Fund (Transformative Quantum Technologies) and the Natural Sciences and Engineering Research Council (NSERC) of Canada. The University of Waterloo's QNFCF Facility was used for this work. This infrastructure would not be possible without the significant contributions of CFREF-TQT, CFI, ISED, the Ontario Ministry of Research and Innovation, and Mike and Ophelia Lazaridis. Their support is gratefully acknowledged.
© 2023 Author(s).