The two-dimensional electron system in an InAs quantum well has emerged as a prime candidate for hosting exotic quasiparticles with non-Abelian statistics such as Majorana fermions and parafermions. To attain its full promise, however, the electron system has to be clean enough to exhibit electron-electron interaction phenomena. Here, we report the observation of the fractional quantum Hall effect in a very low disorder InAs quantum well with a well width of 24 nm, containing a two-dimensional electron system with a density $n=7.8\times {10}^{11}{\mathrm{cm}}^{-2}$ and low-temperature mobility $1.8\times {10}^6{\mathrm{cm}}^2$/Vs. At a temperature of $\simeq 35$ mK and $B\simeq 24$ T, we observe a deep minimum in the longitudinal resistance, accompanied by a nearly quantized Hall plateau at a Landau level filling factor $\nu =4/3$.

• Received 29 August 2017
• Revised 19 October 2017

DOI:https://doi.org/10.1103/PhysRevB.96.241301