title: 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."
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Y P
authors.initials: YP
authors.lastname: Shkolnikov
authors.forename: S
authors.initials: S
authors.lastname: Misra
authors.forename: N C
authors.initials: NC
authors.lastname: Bishop
authors.forename: E P
authors.initials: EP
authors.lastname: De Poortere
authors.forename: M
authors.initials: M
authors.lastname: Shayegan