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arXiv · 2112.05384

Gate tuning of fractional quantum Hall states in InAs two-dimensional electron gas

S. Komatsu·H. Irie·T. Akiho·T. Nojima·T. Akazaki·K. Muraki
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Abstract

We report the observation of fractional quantum Hall (FQH) effects in a two-dimensional electron gas (2DEG) confined to an InAs/AlGaSb quantum well, using a dual-gated Hall-bar device allowing for the independent control of the vertical electric field and electron density. At a magnetic field of 24 T, we observe FQH states at several filling factors, namely $\nu = 5/3$, $2/3$, and $1/3$, in addition to the $\nu = 4/3$ previously reported for an InAs 2DEG. The $\nu = 4/3$ and $5/3$ states, which are absent at zero back-gate voltage, emerge as the quantum well is made more symmetric by applying a positive back-gate voltage. The dependence of zero-field electron mobility on the quantum-well asymmetry reveals a significant contribution of interface-roughness scattering, with much stronger scattering at the lower InAs/AlGaSb interface. However, the dependence of the visibility of the FQH effects on the quantum-well asymmetry is not entirely consistent with that of mobility, suggesting that a different source of disorder is also at work.

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S. Komatsu, H. Irie, T. Akiho, T. Nojima, T. Akazaki, K. Muraki. 2021-12-10. Gate tuning of fractional quantum Hall states in InAs two-dimensional electron gas. https://doi.org/10.1103/physrevb.105.075305

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