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

References in corpus (4)

• Low-temperature, in situ tunable, uniaxial stress measurements in semiconductors using a piezoelectric actuator
• The Two-flux Composite Fermion Series of Fractional Quantum Hall States in Strained Si
• Dependence of spin susceptibility of a two-dimensional electron system on the valley degree of freedom
• Giant low-temperature piezoresistance effect in AlAs two-dimensional electrons