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

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.

arXiv comment5 pages, 4 figures

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Cited by in corpus (2)

• In-plane gate induced transition asymmetry of spin-resolved Landau levels in InAs-based quantum wells
• Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport