NMR profiling of quantum electron solids in high magnetic fields

Abstract

When the motion of electrons is restricted to a plane under a perpendicular magnetic field B, a variety of quantum phases emerge at low temperatures whose properties are dictated by the Coulomb interaction and its interplay with disorder. At very strong B, the sequence of fractional quantum Hall (FQH) liquid phases terminates in an insulating phase, which is widely believed to be due to the solidification of electrons into domains possessing Wigner crystal (WC) order. The existence of such WC domains is signaled by the emergence of microwave pinning-mode resonances, which reflect the mechanical properties characteristic of a solid. However, the most direct manifestation of the broken translational symmetry accompanying the solidification - the spatial modulation of particles' probability amplitude - has not been observed yet. Here, we demonstrate that nuclear magnetic resonance (NMR) provides a direct probe of the density topography of electron solids in the integer and fractional quantum Hall regimes. The data uncover quantum and thermal fluctuation of lattice electrons resolved on the nanometre scale. Our results pave the way to studies of other exotic phases with non-trivial spatial spin/charge order.

A revised version with additional data has been published in Nature Physics 10, 648 (2014)

References in corpus (2)

• Melting of a 2D Quantum Electron Solid in High Magnetic Field
• Microwave Resonance of 2D Wigner Crystal around integer Landau fillings

Cited by in corpus (18)

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• Probing the Melting of a Two-dimensional Quantum Wigner Crystal via its Screening Efficiency
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• Microwave spectroscopic studies of the bilayer electron solid states at low Landau filling in a wide quantum well
• Electron Bubbles and the Structure of the Orbital Wavefunction
• A Highly Correlated Topological Bubble Phase of Composite Fermions
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• Magnetotransport patterns of collective localization near $\nu =1$ in a high-mobility two-dimensional electron gas
• Signatures of correlated defects in an ultra-clean Wigner crystal in the extreme quantum limit
• Stability of multielectron bubbles in high Landau levels
• Thermal Activation Signatures of the Anderson Insulator and the Wigner Solid forming near $\nu =1$
• Density Dependence of the Phases of the $\nu =1$ Integer Quantum Hall Plateau in Low Disorder Electron Gases
• Developing fractional quantum Hall states at $\nu$ = $\frac{1}{7}$ and $\frac{2}{11}$ in the presence of significant Landau level mixing
• Coexistence of two hole phases in high-quality $p$-GaAs/AlGaAs in the vicinity of Landau level filling factors $\nu$=1 and $\nu$=(1/3)
• Nuclear magnetic resonance line shapes of Wigner crystals in ${}^{13}$C-enriched graphene