We report on transport signatures of hidden quantum Hall stripe (hQHS) phases in high (N>2) half-filled Landau levels of AlxGa1-xAs/Al0.24Ga0.76As quantum wells with varying Al mole fraction x<10-3. Residing between the conventional stripe phases (lower N) and the isotropic liquid phases (higher N), where resistivity decreases as 1/N, these hQHS phases exhibit isotropic and N-independent resistivity. Using the experimental phase diagram, we establish that the stripe phases are more robust than theoretically predicted, calling for improved theoretical treatment. We also show that, unlike conventional stripe phases, the hQHS phases do not occur in ultrahigh mobility GaAs quantum wells but are likely to be found in other systems.
Bibliographical noteFunding Information:
We thank G. Jones, T. Murphy, and A. Bangura for technical support. Calculations by Y. H. were supported primarily by the National Science Foundation through the University of Minnesota MRSEC under Grant Nos. DMR-1420013 and DMR-2011401. Experiments by X. F., Q. S., and M. Z. were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award DE-SC0002567. Growth of quantum wells at Purdue University was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award DE-SC0006671. X. F. acknowledges the University of Minnesota Doctoral Dissertation Fellowship. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement Nos. DMR-1157490 and DMR-1644779, and the State of Florida.
© 2020 American Physical Society.
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