@article{95d25f8f166f41a99e61cbd82c040cc4,
title = "Valley-Tunable Even-Denominator Fractional Quantum Hall State in the Lowest Landau Level of an Anisotropic System",
abstract = "Fractional quantum Hall states (FQHSs) at even-denominator Landau level filling factors (ν) are of prime interest as they are predicted to host exotic, topological states of matter. We report here the observation of a FQHS at ν=1/2 in a two-dimensional electron system of exceptionally high quality, confined to a wide AlAs quantum well, where the electrons can occupy multiple conduction-band valleys with an anisotropic effective mass. The anisotropy and multivalley degree of freedom offer an unprecedented tunability of the ν=1/2 FQHS as we can control both the valley occupancy via the application of in-plane strain, and the ratio between the strengths of the short- and long-range Coulomb interaction by tilting the sample in the magnetic field to change the electron charge distribution. Thanks to this tunability, we observe phase transitions from a compressible Fermi liquid to an incompressible FQHS and then to an insulating phase as a function of tilt angle. We find that this evolution and the energy gap of the ν=1/2 FQHS depend strongly on valley occupancy.",
author = "Hossain, {Md Shafayat} and Ma, {Meng K.} and Chung, {Y. J.} and Singh, {S. K.} and A. Gupta and West, {K. W.} and Baldwin, {K. W.} and Pfeiffer, {L. N.} and R. Winkler and M. Shayegan",
note = "Funding Information: We acknowledge support through the U.S. Department of Energy Basic Energy Science (Grant No. DEFG02-00-ER45841) for measurements, and the National Science Foundation (Grants No. DMR 2104771 and No. ECCS 1906253), the Eric and Wendy Schmidt Transformative Technology Fund, and the Gordon and Betty Moore Foundation{\textquoteright}s EPiQS Initiative (Grant No. GBMF9615 to L. N. P.) for sample fabrication and characterization. We also acknowledge QuantEmX travel grants from the Institute for Complex Adaptive Matter and the Gordon and Betty Moore Foundation through Grant No. GBMF5305 to M. S. H., M. K. M., and M. S. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Cooperative Agreement No. DMR-1644779 and the State of Florida. We thank S. Hannahs, T. Murphy, J. Park, H. Baek, and G. Jones at NHMFL for technical support. We also thank J. K. Jain for illuminating discussions. Publisher Copyright: {\textcopyright} 2023 American Physical Society.",
year = "2023",
month = mar,
day = "24",
doi = "10.1103/PhysRevLett.130.126301",
language = "English (US)",
volume = "130",
journal = "Physical review letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "12",
}