TY - JOUR
T1 - Geometric resonance of four-flux composite fermions
AU - Hossain, Md Shafayat
AU - Ma, Meng K.
AU - Mueed, M. A.
AU - Kamburov, D.
AU - Pfeiffer, L. N.
AU - West, K. W.
AU - Baldwin, K. W.
AU - Winkler, R.
AU - Shayegan, M.
N1 - Funding Information:
We acknowledge support through the National Science Foundation (Grants No. DMR 1709076 and No. ECCS 1508925) for measurements, and the National Science Foundation (Grant No. MRSEC DMR 1420541), the US Department of Energy Basic Energy Science (Grant No. DE-FG02-00-ER45841), and the Gordon and Betty Moore Foundation (Grant No. GBMF4420 for sample fabrication and characterization. This research is funded in part by 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 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, W. Pan, M. Ippoliti, and R. N. Bhatt for illuminating discussions.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/7/17
Y1 - 2019/7/17
N2 - Two-dimensional interacting electrons exposed to strong perpendicular magnetic fields generate emergent, exotic quasiparticles phenomenologically distinct from electrons. Specifically, electrons bind with an even number of flux quanta, and transform into composite fermions (CFs). Besides providing an intuitive explanation for the fractional quantum Hall states, CFs also possess Fermi-liquid-like properties, including a well-defined Fermi sea, at and near even-denominator Landau-level filling factors such as ν=1/2 or 1/4. Here, we directly probe the Fermi sea of the rarely studied four-flux CFs near ν=1/4 via geometric resonance experiments. The data reveal some unique characteristics. Unlike in the case of two-flux CFs, the magnetic field positions of the geometric resonance resistance minima for ν<1/4 and ν>1/4 are symmetric with respect to the position of ν=1/4. However, when an in-plane magnetic field is applied, the minima positions become asymmetric, implying a mysterious asymmetry in the CF Fermi sea anisotropy for ν<1/4 and ν>1/4. This asymmetry, which is in stark contrast to the two-flux CFs, suggests that the four-flux CFs on the two sides of ν=1/4 have very different effective masses, possibly because of the proximity of the Wigner crystal formation at small ν.
AB - Two-dimensional interacting electrons exposed to strong perpendicular magnetic fields generate emergent, exotic quasiparticles phenomenologically distinct from electrons. Specifically, electrons bind with an even number of flux quanta, and transform into composite fermions (CFs). Besides providing an intuitive explanation for the fractional quantum Hall states, CFs also possess Fermi-liquid-like properties, including a well-defined Fermi sea, at and near even-denominator Landau-level filling factors such as ν=1/2 or 1/4. Here, we directly probe the Fermi sea of the rarely studied four-flux CFs near ν=1/4 via geometric resonance experiments. The data reveal some unique characteristics. Unlike in the case of two-flux CFs, the magnetic field positions of the geometric resonance resistance minima for ν<1/4 and ν>1/4 are symmetric with respect to the position of ν=1/4. However, when an in-plane magnetic field is applied, the minima positions become asymmetric, implying a mysterious asymmetry in the CF Fermi sea anisotropy for ν<1/4 and ν>1/4. This asymmetry, which is in stark contrast to the two-flux CFs, suggests that the four-flux CFs on the two sides of ν=1/4 have very different effective masses, possibly because of the proximity of the Wigner crystal formation at small ν.
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U2 - 10.1103/PhysRevB.100.041112
DO - 10.1103/PhysRevB.100.041112
M3 - Article
AN - SCOPUS:85070226332
SN - 2469-9950
VL - 100
JO - Physical Review B
JF - Physical Review B
IS - 4
M1 - 041112
ER -