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arXiv · 1904.00828

Quantum transport in high-quality shallow InSb quantum wells

Zijin Lei·Christian A. Lehner·Erik Cheah·Matija Karalic·Christopher Mittag·Luca Alt·Jan Scharnetzky·Werner Wegscheider·Thomas Ihn·Klaus Ensslin
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Abstract

InSb is one of the promising candidates to realize a topological state through proximity induced superconductivity in a material with strong spin-orbit interactions. In two-dimensional systems, thin barriers are needed to allow strong coupling between superconductors and semiconductors. However, it is still challenging to obtain a high-quality InSb two-dimensional electron gas in quantum wells close to the surface. Here we report on a molecular beam epitaxy grown heterostructure of InSb quantum wells with substrate-side Si-doping and ultra-thin InAlSb (5 nm, 25 nm, and 50 nm) barriers to the surface. We demonstrate that the carrier densities in these quantum wells are gate-tunable and electron mobilities up to 350,000 $\rm{cm^2(Vs)^{-1}}$ are extracted from magneto-transport measurements. Furthermore, from temperature-dependent magneto-resistance measurements, we extract an effective mass of 0.02 $m_0$ and find a Zeeman splitting compatible with the expected g-factor.

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Zijin Lei, Christian A. Lehner, Erik Cheah, Matija Karalic, Christopher Mittag, Luca Alt, Jan Scharnetzky, Werner Wegscheider, Thomas Ihn, Klaus Ensslin. 2019-04-01. Quantum transport in high-quality shallow InSb quantum wells. https://doi.org/10.1063/1.5098294

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