SU(4) Skyrmions in the $\nu=\pm$1 Quantum Hall State of Graphene
Résumé
We explore different Skyrmion types in the lowest Landau level of graphene at a filling factor ν=±1. In addition to the formation of spin and valley pseudospin Skyrmions, we show that another type of spin-valley entangled Skyrmions can be stabilized in graphene due to an approximate SU(4) spin-valley symmetry that is affected by sublattice symmetry-breaking terms. These Skyrmions have a clear signature in spin-resolved density measurements on the lattice scale, and we discuss the expected patterns for the different Skyrmion types.