We report the fabrication and operation of a source-drain-gate three-terminal field-effect electronic device with an electron mobility exceeding 40×106 cm2 / (Vs). Several devices were fabricated, with the highest achieved electron mobility obtained using a symmetrically-doped GaAs/AlGaAs quantum well forming a two-dimensional electron gas (2DEG) with a density of 1.47(1)×1011 cm−2 and a pristine, pre-fabrication electron mobility of 44(2)×106 cm2/(\text{Vs}). To circumvent the well-known degradation of electron mobility during fabrication, devices were fabricated using a flip-chip technique where all lithographic processing steps were performed on a separate sapphire substrate. This method demonstrates the successful operation of various gate assembly designs on distinct 2DEGs without observable mobility degradation. This advance doubles the previous record for field-effect electronic device mobility and enables access to new regimes of quantum transport and applications that were previously unfathomable due to mobility limitations.
@article{arxiv.2601.15418,
title = {Demonstration of a Field-Effect Three-Terminal Electronic Device with an Electron Mobility Exceeding 40 Million cm^2/(Vs)},
author = {T. J. Martz-Oberlander and B. Bulgaru and Z. Berkson-Korenberg and Q. Hawkins and K. W. West and K. W. Baldwin and A. Gupta and L. N. Pfeiffer and G. Gervais},
journal= {arXiv preprint arXiv:2601.15418},
year = {2026}
}