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arXiv · 1801.02139

Cyclotron Orbits of Composite Fermions in the Fractional Quantum Hall Regime

Insun Jo·Hao Deng·Yang Liu·L. N. Pfeiffer·K. W. West·K. W. Baldwin·M. Shayegan
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Abstract

We study a bilayer GaAs hole system that hosts two distinct many-body phases at low temperatures and high perpendicular magnetic fields. The higher-density (top) layer develops a Fermi sea of composite fermions (CFs) in its half-filled lowest Landau level, while the lower-density (bottom) layer forms a Wigner crystal (WC) as its filling becomes very small. Owing to the inter-layer interaction, the CFs in the top-layer feel the periodic Coulomb potential of the WC in the bottom-layer. We measure the magnetoresistance of the top-layer while changing the bottom-layer density. As the WC layer density increases, the resistance peaks separating the adjacent fractional quantum Hall states in the top-layer change nonmonotonically and attain maximum values when the cyclotron orbit of the CFs encloses one WC lattice point. These features disappear at T = 275 mK when the WC melts. The observation of such geometric resonance features is unprecedented and surprising as it implies that the CFs retain a well-defined cyclotron orbit and Fermi wave vector even deep in the fractional quantum Hall regime, far from half-filling.

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Insun Jo, Hao Deng, Yang Liu, L. N. Pfeiffer, K. W. West, K. W. Baldwin, M. Shayegan. 2018-01-07. Cyclotron Orbits of Composite Fermions in the Fractional Quantum Hall Regime. https://doi.org/10.1103/physrevlett.120.016802

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