Observation of Quantum Hall Valley Skyrmions

Abstract

We report measurements of the interaction-induced quantum Hall effect in a spin-polarized AlAs two-dimensional electron system where the electrons occupy two in-plane conduction band valleys. Via the application of in-plane strain, we tune the energies of these valleys and measure the energy gap of the quantum Hall state at filling factor $\nu$ = 1. The gap has a finite value even at zero strain and, with strain, rises much faster than expected from a single-particle picture, suggesting that the lowest energy charged excitations at $\nu =1$ are "valley Skyrmions".

4 pages, 3 figures

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• Multicomponent Skyrmion lattices and their excitations
• Robust Quantum Hall Ferromagnetism near a Gate-Tuned ν = 1 Landau Level Crossing
• Realization of a Valley Superlattice
• Parallel Magnetic Field Tuning of Valley Splitting in AlAs Two-Dimensional Electrons
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• Donor binding energy and thermally activated persistent photoconductivity in high mobility (001) AlAs quantum wells
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• Fractional quantum Hall valley ferromagnetism in the extreme quantum limit
• Spontaneous Breaking of the SU(3) Flavor Symmetry in a Quantum Hall Valley Nematic