Proximity Effects in AlGaSb/InAs surface quantum wells
ORAL
Abstract
We demonstrate a robust superconducting proximity effect in 24 nm wide AlGaSb/InAs surface quantum wells with sputtered Nb contacts at a temperature of 1.6 K, which has applications towards mesoscopic and topological superconductivity. Through transport characterization we observe high quality single-subband and second subband magnetotransport with quantized integer quantum Hall plateaus observed to filling factor ν = 2 in magnetic fields of up to B = 18 T. We show that the electron density is gate-tunable, reproducible, and stable from pinchoff to 3 x 1012 cm-2. Landau fan diagrams at high densities exhibit features from the crossing of spin-split Landau levels from different subbands and curvature due to large spin-orbit interaction. A large Rashba spin-orbit coefficient on the order of 100 meV·Å is obtained through weak anti-localization measurements. An effective mass of 0.03me is determined from temperature-dependent magnetoresistance measurements. Josephson junctions fabricated with a contact separation of 200 nm exhibit products IcRN = 495 μV and IexRN = 2.0 mV of normal resistance RN, critical current Ic, and excess current Iex.
*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.
